DVM, Veterinary Sciences & Animal Husbandry, Bidhan Chandra Krishi Viswavidyalaya, India MVSc, Veterinary Virology & Immunology, Indian Veterinary Research Institute, India PhD, Veterinary Virology and Immunology, Indian Veterinary Research Institute, India
Primary Research Interests
- Macaque model
- Pediatric vaccine and immunology
- Viral pathogenesis (Retrovirus, Herpesvirus, Morbillivirus, Flavivirus)
- Viral vaccine and mechanism of correlates of protection
- Intestinal and hepatic cellular plasticity and regeneration.
Loss of intestinal barrier function and subsequent translocation of luminal bacteria are now thought to be the major cause of the chronic systemic immune activation that perpetuates HIV replication and progression to AIDS. We have recently discovered that intestinal epithelial cell (iEC) apoptosis and diminished iEC regeneration occur soon after SIV-infection. Understanding the molecular mechanisms underlying the disrupted iEC regeneration during SIV infection might lead to an alternative approach for the treatment of HIV mediated enteropathy based on iEC recovery. We hypothesize that HIV/SIV infection disrupts the communication between intestinal stem cells and paneth cells leading to diminished iECs regeneration.
Increasing evidence points to a role of non-neutralizing antibodies in protection from HIV infection. We hypothesize that differences in the quality of antigen specific immunoglobulin responses will be observed in macaques in which viral loads are reduced or undetectable compared to RM that have persistent viremia and progress to AIDS. We are investigating the role of antigen specific immunoglobulin, memory B cells, and plasmablasts in SIV infected RM to understand the B cell biology and its impact on SIV infection and pathogenesis. These studies will make significant contributions to our understanding of B cell immunology and SIV pathogenesis.
My research has contributed in developing live attenuated and recombinant vaccines to prevent HIV infection using rhesus macaque animal model. My study using vesicular stomatitis virus containing West Nile virus (WNV) genes administered intranasally can efficiently induce protective humoral and cellular immune responses against WNV infections in mice. In a macaque study, we have shown that the live-attenuated HSV-1 VC2 vaccine induces potent immune responses including robust IgG1 antibody responses that persist for >250 days post vaccination, helps to mature B cells into plasmablasts, generate more memory B cells and expands follicular T helper cells.
Indian Council of Agricultural Research (ICAR) Senior Research Fellowship for doctoral program, 1995
ICAR national eligibility test certificate for Lecturership/Assistant Professorship, 1995
Council of Scientific and Industrial Research Senior Research Fellowship, 1996
Dr. D. R. Uppal Award for the best Ph.D. thesis in Veterinary Virology, 1999
Elizabeth Glaser Pediatric AIDS Foundation Short-Term Scientific Award, 2001
North-Central California Center for AIDS Research short-term training award, 2002
TUHSC Auxiliary Research Career Development Award, 2010
Dean’s list during MBA program at Tulane University, 2014-2015
Membership of the Tulane Chapter of Beta Gamma Sigma (BGS), the International honorary society for outstanding academic performance in MBA program, 2014
Global Initiative of Academic Networks (GIAN) Program (Ministry of Human Resource Development, Govt of India) participant as a Foreign Faculty at BMS College of Engineering, Bangalore, 2017
Diganta Pan, Arpita Das, Sudesh Srivastav, Vicki Traina Dorge, Peter J Didier, Bapi Pahar* (2019). Lack of T-cell-mediated IL-2 and TNFα production is linked to decreased CD58 expression in intestinal tissue during acute simian immunodeficiency virus infection. Journal of General Virology. 100(1): 26-34. (PMID 30480508)
Brent A. Stanfield*, Bapi Pahar*, Vladimir N. Chouljenko, Ronald Veazey, Konstantin G. Kousoulas (2017). Vaccination with a live-attenuated HSV-1 vaccine (VC2) stimulates germinal center responses resulting in long lived highly neutralizing antibodies, and promotes proliferation of mucosal T-cells in rhesus macaques. Vaccine. 35(4): 536-543. (PMID 28017425)* Both authors contribute equally.
Diganta Pan, Carys S. Kenway-Lynch, Wendy Lala, Ronald S. Veazey, Andrew A. Lackner, Arpita Das, Bapi Pahar (2014). Lack of interleukin-10 mediated anti-inflammatory signals and upregulated interferon gamma production are linked to increased intestinal epithelial cell apoptosis in pathogenic simian immunodeficiency virus infection. Journal of Virology 88(22): 13015-13028 (PMID 25165117).
Bapi Pahar, Angela M. Amedee, Jessica Thomas, Jason P. Dufour, Ping Zhang, Steve Nelson, Ronald S. Veazey, and Gregory J. Bagby (2013). Effects of alcohol consumption on antigen-specific cellular and humoral immune responses to SIV in rhesus macaque. Journal of Acquired Immune Deficiency Syndromes 64(4): 332-341. (PMID 23799411).
Arpita Das, Ronald S. Veazey, Xiaolei Wang, Andrew A. Lackner, Huanbin Xu, Bapi Pahar (2011). Simian immunodeficiency virus infection in rhesus macaques induces selective tissue specific B cell defects in double positive CD21+CD27+ memory B cells. Clinical Immunology. 140: 223-228. (PMID 21622026).
Xiaolei Wang, Arpita Das, Andrew A. Lackner, Ronald S. Veazey and Bapi Pahar (2008). Intestinal double positive CD4+CD8+ T cells of neonatal rhesus macaques are proliferating, activated, and memory cells and primary targets for SIVmac251 infection. Blood. 112: 4981-4990. (PMID: 18820133)
See complete list of Dr. Pahar's publications.
Presentation on “Simian Immunodeficiency Virus: Pathogenesis and Immunity” at the Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, 2010
Presentation on “TGFβ and IL10 produced by regulatory B cells are TLR2 dependent and are capable in suppressing Th1 responses” at Keystone symposia TGFβ in immune responses: from Bench to Bedside (A2), Snowbird Resort, Utah, 2011
Presentation entitled “Internalization of IL10 receptors in intestinal lymphoid cells play a crucial role in SIV mediated enteropathy” at European congress of immunology, Glasgow, Scotland, 2012
Seminar on “The Gastrointestinal Immune System in HIV Infection” in B.M.S. College of Engineering, Bangalore, 2017, hosted by Global Initiative of Academic Networks, Ministry of Human Resource Development, Govt of India
Presentated talk on “HIV/SIV induced intestinal epithelial cell dysfunction” in Research Grant Rounds and Symposium with Dr. Charalabos Pothoulakis at Tulane University Medical School, 2018