Ryan Laboratory

Ongoing Research Projects

1. Immune responses during cholera

In a collaborative effort with researchers at the International Centre for Diarrhoeal Disease Research in Dhaka, Bangladesh (ICDDR,B), we are evaluating immune responses in humans infected with Vibrio cholerae, the cause of cholera.  V. cholerae is endemic in over 50 countries, infects approximately 3-5 million individuals globally, and results in the death of approximately 100,000 individuals each year.  Individuals most affected by cholera are those most impoverished, especially those lacking safe water and sanitary facilities, as well as individuals displaced by war, famine, disasters, and conflict.  Cholera can be explosively epidemic, and the global burden of cholera may well increase with climate change, severe weather events, and increasing urbanization.  V. cholerae is a human-restricted infection, and current cholera vaccines provide relatively short-term protection against disease.  The mediators of protective immunity against cholera are poorly understood.  To address this, we are applying a number of high throughput and platform technologies to assess innate and adaptive immune responses in humans with cholera and their household contacts, stratifying responses in the latter by subsequent protection from disease, and comparing responses in the former to those that occur in recipients of current cholera vaccines.  The goal of these studies is to identify the mediators of protection against cholera, in order to advance improved prevention strategies, as well as to advance vaccine development and deployment.

2. Host-pathogen interactions during typhoid fever

In a collaborative effort with researchers at the International Centre for Diarrhoeal Disease Research in Dhaka, Bangladesh (ICDDR,B), we are evaluating host-pathogen interactions and immune responses in humans infected with Salmonella enterica serotype Typhi (the cause of typhoid fever) and S. Paratyphi (the cause of paratyphoid fever).  Together, S. Typhi and S. Paratyphi cause approximately 20 million cases of enteric fever world-wide, resulting in approximately 200,000 deaths each year.  Most of these deaths occur in impoverished children and young adults.  Although usually caused by S. Typhi, one in four cases of enteric fever is caused by S. Paratyphi in many areas of the world.  S. Typhi and S. Paratyphi are particularly common among urban residents in informal settlements and slums, although any individual lacking safe water and sanitary facilities is at risk of infection.  Vaccines against S. Typhi provide only 50-60% protection against disease for 2-5 years, and, at present, there is no commercially available vaccine against S. Paratyphi.  There is also no good point-of-care test to diagnose individuals with enteric fever, and S. Typhi and S. Paratyphi are becoming increasingly resistant to antimicrobial agents.  To address this,  we are evaluating host-pathogen interactions directly in humans infected with S. Typhi and S. Paratyphi.  We are applying a number of technologies to evaluate innate and adaptive immune responses directly in humans infected with S. Typhi and S. Paratyphi in Bangladesh, and we are evaluating bacterial responses in humans during these human-restricted infections.  The goal of these studies is to develop improved diagnostic assays, antimicrobial agents, and preventative strategies against these infections. 

3. Immunization approaches for enteric infection

A fundamental challenge facing many enteric and mucosal vaccines is their inability to induce long-term protective immunity.  Many of these vaccines may not be prominent inducers of memory cells, which play critical roles in mediating long-term protection against disease.  Using our analysis of memory B and T cell induction during wild-type human enteric infection in Bangladesh, we are evaluating the ability of a number of vaccination approaches and strategies to induce long-term memory responses protective against mucosal and enteric infections, including oral-transcutaneous prime-boosting approaches. 

References:

  1. Cholera.
    Harris JB, LaRocque RC, Qadri F, Ryan ET, Calderwood SB. Lancet. 2012 Jun 30;379(9835):2466-76. PMID: 22748592
  2. Antigen-specific memory T cell responses after vaccination with an oral killed cholera vaccine in Bangladeshi children and comparison with natural cholera.
    Arifuzzaman M, Rashu R, Leung DT, Hosen MI, Bhuiyan TR, Bhuiyan MS, Rahman MA, Khanam F, Saha A, Charles RC, Larocque RC, Weil AA, Clements JD, Holmes RK, Calderwood SB, Harris JB, Ryan ET, Qadri F. Clin Vaccine Immunol. 2012 Jun 27. [Epub ahead of print] PMID: 22739692
  3. Travel medicine.
    Schwartz BS, Larocque RC, Ryan ET. Ann Intern Med. 2012 Jun 5;156(11):ITC61. PMID: 22665823
  4. Memory B cell responses to Vibrio cholerae O1 lipopolysaccharide are associated with protection against infection from household contacts of patients with cholera in Bangladesh.
    Patel SM, Rahman MA, Mohasin M, Riyadh MA, Leung DT, Alam MM, Chowdhury F, Khan AI, Weil AA, Aktar A, Nazim M, LaRocque RC, Ryan ET, Calderwood SB, Qadri F, Harris JB. Clin Vaccine Immunol. 2012 Jun;19(6):842-8. Epub 2012 Apr 18. PMID: 22518009
  5. Immune responses to cholera in children.
    Leung DT, Chowdhury F, Calderwood SB, Qadri F, Ryan ET. Expert Rev Anti Infect Ther. 2012 Apr;10(4):435-44. PMID: 22512753
  6. Factors associated with encephalopathy in patients with Salmonella enterica serotype Typhi bacteremia presenting to a diarrheal hospital in Dhaka, Bangladesh.
    Leung DT, Bogetz J, Itoh M, Ganapathi L, Pietroni MA, Ryan ET, Chisti MJ. Am J Trop Med Hyg. 2012 Apr;86(4):698-702. PMID: 22492156
  7. Memory B cell and other immune responses in children receiving two doses of an oral killed cholera vaccine compared to responses following natural cholera infection in Bangladesh.
    Leung DT, Rahman MA, Mohasin M, Patel SM, Aktar A, Khanam F, Uddin T, Riyadh MA, Saha A, Alam MM, Chowdhury F, Khan AI, Charles R, LaRocque R, Harris JB, Calderwood SB, Qadri F, Ryan ET. Clin Vaccine Immunol. 2012 May;19(5):690-8. Epub 2012 Mar 21. PMID: 22441386
  8. Transcutaneous immunization with a Vibrio cholerae O1 Ogawa synthetic hexasaccharide conjugate following oral whole-cell cholera vaccination boosts vibriocidal responses and induces protective immunity in mice.
    Tarique AA, Kalsy A, Arifuzzaman M, Rollins SM, Charles RC, Leung DT, Harris JB, Larocque RC, Sheikh A, Bhuiyan MS, Saksena R, Clements JD, Calderwood SB, Qadri F, Kovác P, Ryan ET. Clin Vaccine Immunol. 2012 Apr;19(4):594-602. Epub 2012 Feb 22. PMID: 22357651
  9. Systemic antibody responses to the immunodominant p23 antigen and p23 polymorphisms in children with cryptosporidiosis in Bangladesh.
    Borad AJ, Allison GM, Wang D, Ahmed S, Karim MM, Kane AV, Moy J, Hibberd PL, Ajjampur SS, Kang G, Calderwood SB, Ryan ET, Naumova E, Khan WA, Ward HD. Am J Trop Med Hyg. 2012 Feb;86(2):214-22. PMID: 22302851
  10. Individuals with Le(a+b-) blood group have increased susceptibility to symptomatic vibrio cholerae O1 infection.
    Arifuzzaman M, Ahmed T, Rahman MA, Chowdhury F, Rashu R, Khan AI, LaRocque RC, Harris JB, Bhuiyan TR, Ryan ET, Calderwood SB, Qadri F. PLoS Negl Trop Dis. 2011 Dec;5(12):e1413. doi: 10.1371/journal.pntd.0001413. Epub 2011 Dec 27. PMID: 22216364 Free PMC Article
  11. Haiti in the context of the current global cholera pandemic.
    Ryan ET. Emerg Infect Dis. 2011 Nov;17(11):2175-6. No abstract available. PMID: 22204041 Free PMC Article
  12. In vivo expression of Salmonella enterica serotype Typhi genes in the blood of patients with typhoid fever in Bangladesh.
    Sheikh A, Charles RC, Sharmeen N, Rollins SM, Harris JB, Bhuiyan MS, Arifuzzaman M, Khanam F, Bukka A, Kalsy A, Porwollik S, Leung DT, Brooks WA, LaRocque RC, Hohmann EL, Cravioto A, Logvinenko T, Calderwood SB, McClelland M, Graham JE, Qadri F, Ryan ET. PLoS Negl Trop Dis. 2011 Dec;5(12):e1419. Epub 2011 Dec 13. PMID: 22180799 Free PMC Article
  13. Case records of the Massachusetts General Hospital. Case 38-2011. A 34-year-old man with diarrhea and weakness.
    Ryan ET, Cronin CG, Branda JA. N Engl J Med. 2011 Dec 15;365(24):2306-16. No abstract available. PMID: 22168646
  14. Global TravEpiNet: a national consortium of clinics providing care to international travelers--analysis of demographic characteristics, travel destinations, and pretravel healthcare of high-risk US international travelers, 2009-2011.
    LaRocque RC, Rao SR, Lee J, Ansdell V, Yates JA, Schwartz BS, Knouse M, Cahill J, Hagmann S, Vinetz J, Connor BA, Goad JA, Oladele A, Alvarez S, Stauffer W, Walker P, Kozarsky P, Franco-Paredes C, Dismukes R, Rosen J, Hynes NA, Jacquerioz F, McLellan S, Hale D, Sofarelli T, Schoenfeld D, Marano N, Brunette G, Jentes ES, Yanni E, Sotir MJ, Ryan ET; Global TravEpiNet Consortium. Clin Infect Dis. 2012 Feb 15;54(4):455-62. Epub 2011 Dec 5. PMID: 22144534
  15. LPLUNC1 modulates innate immune responses to Vibrio cholerae.
    Shin OS, Uddin T, Citorik R, Wang JP, Della Pelle P, Kradin RL, Bingle CD, Bingle L, Camilli A, Bhuiyan TR, Shirin T, Ryan ET, Calderwood SB, Finberg RW, Qadri F, Larocque RC, Harris JB. J Infect Dis. 2011 Nov;204(9):1349-57. Epub 2011 Sep 7. PMID: 21900486
  16. Simple, direct conjugation of bacterial O-SP-core antigens to proteins: development of cholera conjugate vaccines.
    Xu P, Alam MM, Kalsy A, Charles RC, Calderwood SB, Qadri F, Ryan ET, Kováč P. Bioconjug Chem. 2011 Oct 19;22(10):2179-85. Epub 2011 Sep 30. PMID: 21899371
  17. Cholera in the 21st century.
    Charles RC, Ryan ET. Curr Opin Infect Dis. 2011 Oct;24(5):472-7. Review. PMID: 21799407
  18. Antibody responses to the immunodominant Cryptosporidium gp15 antigen and gp15 polymorphisms in a case-control study of cryptosporidiosis in children in Bangladesh.
    Allison GM, Rogers KA, Borad A, Ahmed S, Karim MM, Kane AV, Hibberd PL, Naumova EN, Calderwood SB, Ryan ET, Khan WA, Ward HD. Am J Trop Med Hyg. 2011 Jul;85(1):97-104. PMID: 21734132 Free PMC Article
  19. Case records of the Massachusetts General Hospital. Case 20-2011. A 30-year-old man with diarrhea after a trip to the Dominican Republic.
    Ryan ET, Madoff LC, Ferraro MJ. N Engl J Med. 2011 Jun 30;364(26):2536-41. No abstract available. PMID: 21714651
  20. Vibrio cholerae O1 infection induces proinflammatory CD4+ T-cell responses in blood and intestinal mucosa of infected humans.
    Kuchta A, Rahman T, Sennott EL, Bhuyian TR, Uddin T, Rashu R, Chowdhury F, Kahn AI, Arifuzzaman M, Weil AA, Podolsky M, LaRocque RC, Ryan ET, Calderwood SB, Qadri F, Harris JB. Clin Vaccine Immunol. 2011 Aug;18(8):1371-7. Epub 2011 Jun 22. PMID: 21697339 Free PMC Article
  21. Comparison of memory B cell, antibody-secreting cell, and plasma antibody responses in young children, older children, and adults with infection caused by Vibrio cholerae O1 El Tor Ogawa in Bangladesh.
    Leung DT, Rahman MA, Mohasin M, Riyadh MA, Patel SM, Alam MM, Chowdhury F, Khan AI, Kalivoda EJ, Aktar A, Bhuiyan MS, LaRocque RC, Harris JB, Calderwood SB, Qadri F, Ryan ET. Clin Vaccine Immunol. 2011 Aug;18(8):1317-25. Epub 2011 Jun 22. PMID: 21697337 Free PMC Article
  22. Interferon-γ and proliferation responses to Salmonella enterica Serotype Typhi proteins in patients with S. Typhi Bacteremia in Dhaka, Bangladesh.
    Sheikh A, Khanam F, Sayeed MA, Rahman T, Pacek M, Hu Y, Rollins A, Bhuiyan MS, Rollins S, Kalsy A, Arifuzzaman M, Leung DT, Sarracino DA, Krastins B, Charles RC, Larocque RC, Cravioto A, Calderwood SB, Brooks WA, Harris JB, Labaer J, Qadri F, Ryan ET. PLoS Negl Trop Dis. 2011 Jun;5(6):e1193. Epub 2011 Jun 7. PMID: 21666798 Free PMC Article
  23. Meeting cholera's challenge to Haiti and the world: a joint statement on cholera prevention and care.
    Farmer P, Almazor CP, Bahnsen ET, Barry D, Bazile J, Bloom BR, Bose N, Brewer T, Calderwood SB, Clemens JD, Cravioto A, Eustache E, Jérôme G, Gupta N, Harris JB, Hiatt HH, Holstein C, Hotez PJ, Ivers LC, Kerry VB, Koenig SP, Larocque RC, Léandre F, Lambert W, Lyon E, Mekalanos JJ, Mukherjee JS, Oswald C, Pape JW, Gretchko Prosper A, Rabinovich R, Raymonville M, Réjouit JR, Ronan LJ, Rosenberg ML, Ryan ET, Sachs JD, Sack DA, Surena C, Suri AA, Ternier R, Waldor MK, Walton D, Weigel JL. PLoS Negl Trop Dis. 2011;5(5):e1145. Epub 2011 May 31. Review. No abstract available. PMID: 21655350 Free PMC Article
  24. Genetic diversity of Cryptosporidium spp. from Bangladeshi children.
    Hira KG, Mackay MR, Hempstead AD, Ahmed S, Karim MM, O'Connor RM, Hibberd PL, Calderwood SB, Ryan ET, Khan WA, Ward HD. J Clin Microbiol. 2011 Jun;49(6):2307-10. Epub 2011 Apr 6. PMID: 21471344 Free PMC Article
  25. Antigen-specific memory B-cell responses in Bangladeshi adults after one or two dose oral killed cholera vaccination, and comparison with responses following natural cholera.
    Alam MM, Riyadh MA, Fatema K, Rahman MA, Akhtar N, Ahmed T, Chowdhury MI, Chowdhury F, Calderwood SB, Harris JB, Ryan ET, Qadri F.Clin Vaccine Immunol. 2011 Feb 23. [Epub ahead of print] PMID: 21346055
  26. The cholera pandemic, still with us after half a century: time to rethink.
    Ryan ET. PLoS Negl Trop Dis. 2011 Jan 25;5(1):e1003. No abstract available.  PMID: 21283611
  27. Mucosal immunologic responses in cholera patients in bangladesh.
    Uddin T, Harris JB, Bhuiyan TR, Shirin T, Uddin MI, Khan AI, Chowdhury F, Larocque RC, Alam NH, Ryan ET, Calderwood SB, Qadri F.Clin Vaccine Immunol. 2011 Mar;18(3):506-12. Epub 2011 Jan 19. PMID: 21248157
  28. Severe, acute watery diarrhea in an adult.
    Chowdhury F, Khan AI, Faruque AS, Ryan ET. PLoS Negl Trop Dis. 2010 Nov 30;4(11):e898. No abstract available.  PMID: 21152053
  29. Analysis of Salmonella enterica serotype paratyphi A gene expression in the blood of bacteremic patients in Bangladesh.
    Sheikh A, Charles RC, Rollins SM, Harris JB, Bhuiyan MS, Khanam F, Bukka A, Kalsy A, Porwollik S, Brooks WA, LaRocque RC, Hohmann EL, Cravioto A, Logvinenko T, Calderwood SB, McClelland M, Graham JE, Qadri F, Ryan ET. PLoS Negl Trop Dis. 2010 Dec 7;4(12):e908. PMID: 21151879
  30. Relatedness of Vibrio cholerae O1/O139 isolates from patients and their household contacts, determined by multilocus variable-number tandem-repeat analysis.
    Kendall EA, Chowdhury F, Begum Y, Khan AI, Li S, Thierer JH, Bailey J, Kreisel K, Tacket CO, LaRocque RC, Harris JB, Ryan ET, Qadri F, Calderwood SB, Stine OC. J Bacteriol. 2010 Sep;192(17):4367-76. Epub 2010 Jun 28. PMID: 20585059
  31. Characterization of anti-Salmonella enterica serotype Typhi antibody responses in bacteremic Bangladeshi patients by an immunoaffinity proteomics-based technology.
    Charles RC, Sheikh A, Krastins B, Harris JB, Bhuiyan MS, LaRocque RC, Logvinenko T, Sarracino DA, Kudva IT, Eisenstein J, Podolsky MJ, Kalsy A, Brooks WA, Ludwig A, John M, Calderwood SB, Qadri F, Ryan ET.Clin Vaccine Immunol. 2010 Aug;17(8):1188-95. Epub 2010 Jun 23. PMID: 20573880
  32. Informal urban settlements and cholera risk in Dar es Salaam, Tanzania.
    Penrose K, de Castro MC, Werema J, Ryan ET.PLoS Negl Trop Dis. 2010 Mar 16;4(3):e631. PMID: 20300569
  33. Concomitant enterotoxigenic Escherichia coli infection induces increased immune responses to Vibrio cholerae O1 antigens in patients with cholera in Bangladesh.
    Chowdhury F, Begum YA, Alam MM, Khan AI, Ahmed T, Bhuiyan MS, Harris JB, LaRocque RC, Faruque AS, Endtz H, Ryan ET, Cravioto A, Svennerholm AM, Calderwood SB, Qadri F. Infect Immun. 2010 May;78(5):2117-24. Epub 2010 Feb 22. PMID: 20176796
  34. Familial aggregation of Vibrio cholerae-associated infection in Matlab, Bangladesh.
    Rahman KM, Duggal P, Harris JB, Saha SK, Streatfield PK, Ryan ET, Calderwood SB, Qadri F, Yunus M, LaRocque RC.J Health Popul Nutr. 2009 Dec;27(6):733-8. PMID: 20099756
  35. Comparison of clinical features and immunological parameters of patients with dehydrating diarrhoea infected with Inaba or Ogawa serotypes of Vibrio cholerae O1.
    Khan AI, Chowdhury F, Harris JB, Larocque RC, Faruque AS, Ryan ET, Calderwood SB, Qadri F. Scand J Infect Dis. 2009 Nov 2. PMID: 19883159
  36. Development of IgM memory to both a T cell-independent and a T cell-dependent antigen following infection with Vibrio cholerae O1 in Bangladesh.
    Kendall EA, Tarique AA, Hossain A, Alam MM, Arifuzzaman M, Akhtar N, Chowdhury F, Khan AI, Larocque RC, Harris JB, Ryan ET, Qadri F, Calderwood SB.
    Infect Immun. 2009 Oct 26. PMID: 19858296
  37. Clinical outcomes in household contacts of patients with cholera in bangladesh.
    Weil AA, Khan AI, Chowdhury F, Larocque RC, Faruque AS, Ryan ET, Calderwood SB, Qadri F, Harris JB. Clin Infect Dis. 2009 Nov 15;49(10):1473-9.PMID: 19842974
  38. Comparative proteomic analysis of the PhoP regulon in Salmonella enterica serovar Typhi versus Typhimurium.
    Charles RC, Harris JB, Chase MR, Lebrun LM, Sheikh A, LaRocque RC, Logvinenko T, Rollins SM, Tarique A, Hohmann EL, Rosenberg I, Krastins B, Sarracino DA, Qadri F, Calderwood SB, Ryan ET. PLoS One. 2009 Sep 10;4(9):e6994.PMID: 19746165 Free article
  39. Salmonella enterica serovar Typhi-specific immunoglobulin A antibody responses in plasma and antibody in lymphocyte supernatant specimens in Bangladeshi patients with suspected typhoid fever.
    Sheikh A, Bhuiyan MS, Khanam F, Chowdhury F, Saha A, Ahmed D, Jamil KM, LaRocque RC, Harris JB, Ahmad MM, Charles R, Brooks WA, Calderwood SB, Cravioto A, Ryan ET, Qadri F. Clin Vaccine Immunol. 2009 Nov;16(11):1587-94. Epub 2009 Sep 9.PMID: 19741090
  40. Memory T-cell responses to Vibrio cholerae O1 infection.
    Weil AA, Arifuzzaman M, Bhuiyan TR, LaRocque RC, Harris AM, Kendall EA, Hossain A, Tarique AA, Sheikh A, Chowdhury F, Khan AI, Murshed F, Parker KC, Banerjee KK, Ryan ET, Harris JB, Qadri F, Calderwood SB. Infect Immun. 2009 Nov;77(11):5090-6. Epub 2009 Aug 24.PMID: 19703973
  41. Vaccination of children in low-resource countries against Shigella is unlikely to present an undue risk of reactive arthritis.
    Gaston JS, Inman RD, Ryan ET, Venkatesan MM, Barry EM, Hale TL, Bourgeois AL, Walker RI. Vaccine. 2009 Sep 4;27(40):5432-4. Epub 2009 Jul 28.PMID:
  42. Transcutaneous immunization with a synthetic hexasaccharide-protein conjugate induces anti-Vibrio cholerae lipopolysaccharide responses in mice.
    Rollenhagen JE, Kalsy A, Saksena R, Sheikh A, Alam MM, Qadri F, Calderwood SB, Kovác P, Ryan ET. Vaccine. 2009 Aug 6;27(36):4917-22. Epub 2009 Jun 27.PMID: 19563890
  43. Antigen-specific memory B-cell responses to Vibrio cholerae O1 infection in Bangladesh.
    Harris AM, Bhuiyan MS, Chowdhury F, Khan AI, Hossain A, Kendall EA, Rahman A, LaRocque RC, Wrammert J, Ryan ET, Qadri F, Calderwood SB, Harris JB.
    Infect Immun. 2009 Sep;77(9):3850-6. Epub 2009 Jun 15.PMID: 19528207
  44. Immunologic Responses to Vibrio cholerae in Patients Co-Infected with Intestinal Parasites in Bangladesh.
    Harris JB, Podolsky MJ, Bhuiyan TR, Chowdhury F, Khan AI, Larocque RC, Logvinenko T, Kendall J, Faruque AS, Nagler CR, Ryan ET, Qadri F, Calderwood SB.
    PLoS Negl Trop Dis. 2009;3(3):e403. Epub 2009 Mar 31.PMID: 19333369 Free article
  45. A variant in long palate, lung and nasal epithelium clone 1 is associated with cholera in a Bangladeshi population.
    Larocque RC, Sabeti P, Duggal P, Chowdhury F, Khan AI, Lebrun LM, Harris JB, Ryan ET, Qadri F, Calderwood SB.
    Genes Immun. 2009 Apr;10(3):267-72. Epub 2009 Feb 12.PMID: 19212328 Free article
  46. Shifting prevalence of major diarrheal pathogens in patients seeking hospital care during floods in 1998, 2004, and 2007 in Dhaka, Bangladesh.
    Harris AM, Chowdhury F, Begum YA, Khan AI, Faruque AS, Svennerholm AM, Harris JB, Ryan ET, Cravioto A, Calderwood SB, Qadri F.
    Am J Trop Med Hyg. 2008 Nov;79(5):708-14.PMID: 18981509 Free article
  47. Management of travellers' diarrhoea.
    Hill DR, Ryan ET.
    BMJ. 2008 Oct 6;337:a1746. doi: 10.1136/bmj.a1746. Review. No abstract available. PMID: 18838421
  48. A comparison of clinical and immunologic features in children and older patients hospitalized with severe cholera in Bangladesh.
    Chowdhury F, Khan AI, Harris JB, LaRocque RC, Chowdhury MI, Ryan ET, Faruque AS, Calderwood SB, Qadri F.
    Pediatr Infect Dis J. 2008 Nov;27(11):986-92.PMID: 18833030 Free article
  49. Cholera toxin-specific memory B cell responses are induced in patients with dehydrating diarrhea caused by Vibrio cholerae O1.
    Jayasekera CR, Harris JB, Bhuiyan S, Chowdhury F, Khan AI, Faruque AS, Larocque RC, Ryan ET, Ahmed R, Qadri F, Calderwood SB.
    J Infect Dis. 2008 Oct 1;198(7):1055-61.PMID: 18729782 Free article
  50. Proteomic analysis of Vibrio cholerae in human stool.
    LaRocque RC, Krastins B, Harris JB, Lebrun LM, Parker KC, Chase M, Ryan ET, Qadri F, Sarracino D, Calderwood SB.
    Infect Immun. 2008 Sep;76(9):4145-51. Epub 2008 Jun 30.PMID: 18591230 Free article
  51. Susceptibility to Vibrio cholerae Infection in a Cohort of Household Contacts of Patients with Cholera in Bangladesh.
    Harris JB, Larocque RC, Chowdhury F, Khan AI, Logvinenko T, Faruque AS, Ryan ET, Qadri F, Calderwood SB.
    PLoS Negl Trop Dis. 2008 Apr 9;2(4):e221.PMID: 18398491 Free article
  52. Application of in vivo induced antigen technology (IVIAT) to Bacillus anthracis.
    Rollins SM, Peppercorn A, Young JS, Drysdale M, Baresch A, Bikowski MV, Ashford DA, Quinn CP, Handfield M, Hillman JD, Lyons CR, Koehler TM, Calderwood SB, Ryan ET.
    PLoS One. 2008 Mar 19;3(3):e1824.PMID: 18350160 Free article
  53. Complexity of rice-water stool from patients with Vibrio cholerae plays a role in the transmission of infectious diarrhea.
    Nelson EJ, Chowdhury A, Harris JB, Begum YA, Chowdhury F, Khan AI, Larocque RC, Bishop AL, Ryan ET, Camilli A, Qadri F, Calderwood SB.
    Proc Natl Acad Sci U S A. 2007 Nov 27;104(48):19091-6. Epub 2007 Nov 16.PMID: 18024592 Free article
  54. Case records of the Massachusetts General Hospital. Case 29-2007. A 51-year-old man with gastric cancer and lung nodules.
    Ryan ET, Aquino SL, Kradin RL.
    N Engl J Med. 2007 Sep 20;357(12):1239-46. No abstract available. PMID: 17881756
  55. Bacteremia, fever, and splenomegaly caused by a newly recognized bartonella species.
    Eremeeva ME, Gerns HL, Lydy SL, Goo JS, Ryan ET, Mathew SS, Ferraro MJ, Holden JM, Nicholson WL, Dasch GA, Koehler JE.
    N Engl J Med. 2007 Jun 7;356(23):2381-7.PMID: 17554119 Free article
  56. Transcutaneous immunization with Clostridium difficile toxoid A induces systemic and mucosal immune responses and toxin A-neutralizing antibodies in mice.
    Ghose C, Kalsy A, Sheikh A, Rollenhagen J, John M, Young J, Rollins SM, Qadri F, Calderwood SB, Kelly CP, Ryan ET.
    Infect Immun. 2007 Jun;75(6):2826-32. Epub 2007 Mar 19.PMID: 17371854 Free article
  57. The practice of travel medicine: guidelines by the Infectious Diseases Society of America.
    Hill DR, Ericsson CD, Pearson RD, Keystone JS, Freedman DO, Kozarsky PE, DuPont HL, Bia FJ, Fischer PR, Ryan ET; Infectious Diseases Society of America.
    Clin Infect Dis. 2006 Dec 15;43(12):1499-539. Epub 2006 Nov 8. No abstract available. PMID: 17109284
  58. Live attenuated oral cholera vaccines.
    Ryan ET, Calderwood SB, Qadri F.
    Expert Rev Vaccines. 2006 Aug;5(4):483-94. Review.PMID: 16989629
  59. Transcutaneous immunization with toxin-coregulated pilin A induces protective immunity against Vibrio cholerae O1 El Tor challenge in mice.
    Rollenhagen JE, Kalsy A, Cerda F, John M, Harris JB, Larocque RC, Qadri F, Calderwood SB, Taylor RK, Ryan ET.
    Infect Immun. 2006 Oct;74(10):5834-9.PMID: 16988262 Free article
  60. Primaquine: report from CDC expert meeting on malaria chemoprophylaxis I.
    Hill DR, Baird JK, Parise ME, Lewis LS, Ryan ET, Magill AJ.
    Am J Trop Med Hyg. 2006 Sep;75(3):402-15.PMID: 16968913 Free article
    Infectious diseases of severe weather-related and flood-related natural disasters.
    Ivers LC, Ryan ET.
    Curr Opin Infect Dis. 2006 Oct;19(5):408-14. Review.PMID: 16940862
  61. Identification of in vivo-induced bacterial protein antigens during human infection with Salmonella enterica serovar Typhi.
    Harris JB, Baresch-Bernal A, Rollins SM, Alam A, LaRocque RC, Bikowski M, Peppercorn AF, Handfield M, Hillman JD, Qadri F, Calderwood SB, Hohmann E, Breiman RF, Brooks WA, Ryan ET.
    Infect Immun. 2006 Sep;74(9):5161-8.PMID: 16926408 Free article
  62. Postgenomic approaches to cholera vaccine development.
    LaRocque RC, Harris JB, Ryan ET, Qadri F, Calderwood SB.
    Expert Rev Vaccines. 2006 Jun;5(3):337-46. Review.PMID: 16827618
  63. Diarrheal epidemics in Dhaka, Bangladesh, during three consecutive floods: 1988, 1998, and 2004.
    Schwartz BS, Harris JB, Khan AI, Larocque RC, Sack DA, Malek MA, Faruque AS, Qadri F, Calderwood SB, Luby SP, Ryan ET.
    Am J Trop Med Hyg. 2006 Jun;74(6):1067-73.PMID: 16760521 Free article
  64. Low risk of hemolytic uremic syndrome after early effective antimicrobial therapy for Shigella dysenteriae type 1 infection in Bangladesh.
    Bennish ML, Khan WA, Begum M, Bridges EA, Ahmed S, Saha D, Salam MA, Acheson D, Ryan ET.
    Clin Infect Dis. 2006 Feb 1;42(3):356-62. Epub 2005 Dec 21.PMID: 16392080
  65. Case records of the Massachusetts General Hospital. Case 39-2005. A 63-year-old woman with a positive serologic test for syphilis and persistent eosinophilia.
    Ryan ET, Felsenstein D, Aquino SL, Branda JA, Morgan JG.
    N Engl J Med. 2005 Dec 22;353(25):2697-705. No abstract available. PMID: 16371636
  66. Blood group, immunity, and risk of infection with Vibrio cholerae in an area of endemicity.
    Harris JB, Khan AI, LaRocque RC, Dorer DJ, Chowdhury F, Faruque AS, Sack DA, Ryan ET, Qadri F, Calderwood SB.
    Infect Immun. 2005 Nov;73(11):7422-7.PMID: 16239542 Free article
  67. Hyperinfectivity of human-passaged Vibrio cholerae can be modeled by growth in the infant mouse.
    Alam A, Larocque RC, Harris JB, Vanderspurt C, Ryan ET, Qadri F, Calderwood SB.
    Infect Immun. 2005 Oct;73(10):6674-9.PMID: 16177344 Free article
  68. Reduction in capsular content and enhanced bacterial susceptibility to serum killing of Vibrio cholerae O139 associated with the 2002 cholera epidemic in Bangladesh.
    Qadri F, Svennerholm AM, Shamsuzzaman S, Bhuiyan TR, Harris JB, Ghosh AN, Nair GB, Weintraub A, Faruque SM, Ryan ET, Sack DA, Calderwood SB.
    Infect Immun. 2005 Oct;73(10):6577-83.PMID: 16177333 Free article
  69. Species-specific bacteria identification using differential mobility spectrometry and bioinformatics pattern recognition.
    Shnayderman M, Mansfield B, Yip P, Clark HA, Krebs MD, Cohen SJ, Zeskind JE, Ryan ET, Dorkin HL, Callahan MV, Stair TO, Gelfand JA, Gill CJ, Hitt B, Davis CE.
    Anal Chem. 2005 Sep 15;77(18):5930-7.PMID: 16159124
  70. Transcriptional profiling of Vibrio cholerae recovered directly from patient specimens during early and late stages of human infection.
    Larocque RC, Harris JB, Dziejman M, Li X, Khan AI, Faruque AS, Faruque SM, Nair GB, Ryan ET, Qadri F, Mekalanos JJ, Calderwood SB.
    Infect Immun. 2005 Aug;73(8):4488-93.PMID: 16040959 Free article
  71. Transformation of the developing world: socioeconomic matrix.
    Carroll D, Gardner P, Kay BA, Osterholm M, Ryan ET.
    Emerg Infect Dis. 2004 Nov;10(11):2049. No abstract available. PMID: 16010742
  72. Case records of the Massachusetts General Hospital. Case 19-2005. A 17-year-old girl with respiratory distress and hemiparesis after surviving a tsunami.
    Kao AY, Munandar R, Ferrara SL, Systrom DM, Sheridan RL, Cash SS, Ryan ET.
    N Engl J Med. 2005 Jun 23;352(25):2628-36. No abstract available. PMID: 15972870
  73. Prevention of infection in adult travelers after solid organ transplantation.
    Kotton CN, Ryan ET, Fishman JA.
    Am J Transplant. 2005 Jan;5(1):8-14. Review.PMID: 15636606
  74. In vivo induced antigen technology (IVIAT).
    Rollins SM, Peppercorn A, Hang L, Hillman JD, Calderwood SB, Handfield M, Ryan ET.
    Cell Microbiol. 2005 Jan;7(1):1-9. Review.PMID: 15617518
  75. Cryptosporidiosis among Bangladeshi children with diarrhea: a prospective, matched, case-control study of clinical features, epidemiology and systemic antibody responses.
    Khan WA, Rogers KA, Karim MM, Ahmed S, Hibberd PL, Calderwood SB, Ryan ET, Ward HD.
    Am J Trop Med Hyg. 2004 Oct;71(4):412-9.PMID: 15516636 Free article
  76. The major subunit of the toxin-coregulated pilus TcpA induces mucosal and systemic immunoglobulin A immune responses in patients with cholera caused by Vibrio cholerae O1 and O139.
    Asaduzzaman M, Ryan ET, John M, Hang L, Khan AI, Faruque AS, Taylor RK, Calderwood SB, Qadri F.
    Infect Immun. 2004 Aug;72(8):4448-54.PMID: 15271902 Free article
  77. Incomplete correlation of serum vibriocidal antibody titer with protection from Vibrio cholerae infection in urban Bangladesh.
    Saha D, LaRocque RC, Khan AI, Harris JB, Begum YA, Akramuzzaman SM, Faruque AS, Ryan ET, Qadri F, Calderwood SB.
    J Infect Dis. 2004 Jun 15;189(12):2318-22. Epub 2004 May 25.PMID: 15181581
  78. Medical problems in the returning expatriate.
    Hochberg N, Ryan ET.
    Clin Occup Environ Med. 2004 Feb;4(1):205-19. Review.PMID: 15043371
  79. Vaccination strategies.
    Ivers LC, Ryan ET.
    Clin Occup Environ Med. 2004 Feb;4(1):27-43.PMID: 15043362
  80. Yersinia pestis and the plague.
    Rollins SE, Rollins SM, Ryan ET.
    Am J Clin Pathol. 2003 Jun;119 Suppl:S78-85. Review.PMID: 12951845
  81. Antigen-specific immunoglobulin A antibodies secreted from circulating B cells are an effective marker for recent local immune responses in patients with cholera: comparison to antibody-secreting cell responses and other immunological markers.
    Qadri F, Ryan ET, Faruque AS, Ahmed F, Khan AI, Islam MM, Akramuzzaman SM, Sack DA, Calderwood SB.
    Infect Immun. 2003 Aug;71(8):4808-14.PMID: 12874365 Free article
  82. Use of in vivo-induced antigen technology (IVIAT) to identify genes uniquely expressed during human infection with Vibrio cholerae.
    Hang L, John M, Asaduzzaman M, Bridges EA, Vanderspurt C, Kirn TJ, Taylor RK, Hillman JD, Progulske-Fox A, Handfield M, Ryan ET, Calderwood SB.
    Proc Natl Acad Sci U S A. 2003 Jul 8;100(14):8508-13. Epub 2003 Jun 25.PMID: 12826608 Free article
  83. Images in clinical medicine. Thoracic echinococcosis.
    Brainard DM, Ryan ET.
    N Engl J Med. 2003 Feb 6;348(6):528. No abstract available. PMID: 12571260
  84. Illness after international travel.
    Ryan ET, Wilson ME, Kain KC.
    N Engl J Med. 2002 Aug 15;347(7):505-16. Review. No abstract available. PMID: 12181406
  85. Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 20-2002. A 37-year-old man with fever, hepatosplenomegaly, and a cutaneous foot lesion after a trip to Africa.
    Moore AC, Ryan ET, Waldron MA.
    N Engl J Med. 2002 Jun 27;346(26):2069-76. No abstract available. PMID: 12087144
  86. Comparison of mucosal and systemic humoral immune responses after transcutaneous and oral immunization strategies.
    John M, Bridges EA, Miller AO, Calderwood SB, Ryan ET.
    Vaccine. 2002 Jun 21;20(21-22):2720-6.PMID: 12034098
  87. Malaria: epidemiology, pathogenesis, diagnosis, prevention, and treatment--an update.
    Ryan ET.
    Curr Clin Top Infect Dis. 2001;21:83-113. Review. No abstract available. PMID: 11572163
  88. Local production of anti-vibrio cholerae mucosal antibody in reproductive tract tissues after cholera.
    Ryan ET, Bridges EA, Crean TI, Gausia K, Hamadani JD, Aziz A, Hawkes S, Begum M, Bogaerts J, Faruque SM, Salam MA, Fuchs GJ, Calderwood SB.
    J Infect Dis. 2001 Sep 1;184(5):643-7. Epub 2001 Aug 9.PMID: 11494170
  89. Mortality, morbidity, and microbiology of endemic cholera among hospitalized patients in Dhaka, Bangladesh.
    Ryan ET, Dhar U, Khan WA, Salam MA, Faruque AS, Fuchs GJ, Calderwood SB, Bennish ML.
    Am J Trop Med Hyg. 2000 Jul-Aug;63(1-2):12-20.PMID: 11357989 Free article
  90. Cholera vaccines.
    Ryan ET, Calderwood SB.
    J Travel Med. 2001 Mar-Apr;8(2):82-91. Review. No abstract available. PMID: 11285167
  91. Clostridium difficile--Associated diarrhea: A review.
    Mylonakis E, Ryan ET, Calderwood SB.
    Arch Intern Med. 2001 Feb 26;161(4):525-33. Review.PMID: 11252111 Free article
  92. Cholera vaccines.
    Ryan ET, Calderwood SB.
    Clin Infect Dis. 2000 Aug;31(2):561-5. Epub 2000 Sep 7. Review.PMID: 10987721
  93. Health advice and immunizations for travelers.
    Ryan ET, Kain KC.
    N Engl J Med. 2000 Jun 8;342(23):1716-25. Review. No abstract available. PMID: 10841875
  94. In vitro and in vivo analyses of constitutive and in vivo-induced promoters in attenuated vaccine and vector strains of Vibrio cholerae.
    John M, Crean TI, Calderwood SB, Ryan ET.
    Infect Immun. 2000 Mar;68(3):1171-5.PMID: 10678922 Free article
  95. Optimizing the germfree mouse model for in vivo evaluation of oral Vibrio cholerae vaccine and vector strains.
    Crean TI, John M, Calderwood SB, Ryan ET.
    Infect Immun. 2000 Feb;68(2):977-81.PMID: 10639476 Free article
  96. Development of a DeltaglnA balanced lethal plasmid system for expression of heterologous antigens by attenuated vaccine vector strains of Vibrio cholerae.
    Ryan ET, Crean TI, Kochi SK, John M, Luciano AA, Killeen KP, Klose KE, Calderwood SB.
    Infect Immun. 2000 Jan;68(1):221-6.PMID: 10603391 Free article
  97. In vivo expression and immunoadjuvancy of a mutant of heat-labile enterotoxin of Escherichia coli in vaccine and vector strains of Vibrio cholerae.
    Ryan ET, Crean TI, John M, Butterton JR, Clements JD, Calderwood SB.
    Infect Immun. 1999 Apr;67(4):1694-701.PMID: 10085006 Free article
  98. Oral immunization with attenuated vaccine strains of Vibrio cholerae expressing a dodecapeptide repeat of the serine-rich Entamoeba histolytica protein fused to the cholera toxin B subunit induces systemic and mucosal antiamebic and anti-V. cholerae antibody responses in mice.
    Ryan ET, Butterton JR, Zhang T, Baker MA, Stanley SL Jr, Calderwood SB.
    Infect Immun. 1997 Aug;65(8):3118-25.PMID: 9234763 Free article
  99. Protective immunity against Clostridium difficile toxin A induced by oral immunization with a live, attenuated Vibrio cholerae vector strain.
    Ryan ET, Butterton JR, Smith RN, Carroll PA, Crean TI, Calderwood SB.
    Infect Immun. 1997 Jul;65(7):2941-9.PMID: 9199470 Free article
  100. Coexpression of the B subunit of Shiga toxin 1 and EaeA from enterohemorrhagic Escherichia coli in Vibrio cholerae vaccine strains.
    Butterton JR, Ryan ET, Acheson DW, Calderwood SB.
    Infect Immun. 1997 Jun;65(6):2127-35.PMID: 9169742 Free article
  101. Development of a germfree mouse model of Vibrio cholerae infection.
    Butterton JR, Ryan ET, Shahin RA, Calderwood SB.
    Infect Immun. 1996 Oct;64(10):4373-7.PMID: 8926115 Free article
  102. Parasitic infections of the anterior segment.
    Young JA, Ryan ET.
    Int Ophthalmol Clin. 1996 Summer;36(3):49-71. Review. No abstract available. PMID: 8989600
  103. Myocardial infarction mimicked by acute cholecystitis.
    Ryan ET, Pak PH, DeSanctis RW.
    Ann Intern Med. 1992 Feb 1;116(3):218-20. No abstract available. PMID: 1728205
  104. Hirschsprung's disease: associated abnormalities and demography.
    Ryan ET, Ecker JL, Christakis NA, Folkman J.
    J Pediatr Surg. 1992 Jan;27(1):76-81.PMID: 1552451
  105. Polyclonal B-cell lymphocytosis and hypergammaglobulinemia in patients with Gaucher disease.
    Marti GE, Ryan ET, Papadopoulos NM, Filling-Katz M, Barton N, Fleischer TA, Rick M, Gralnick HR.
    Am J Hematol. 1988 Dec;29(4):189-94.PMID: 3263798
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