Priya, R and Sulochana, D D (2008) Expression of co-stimulatory molecules B7.1 & B7.2 on macrophages infected with various strains of Mycobacterium tuberculosis & its influence on T-cell apoptosis. Indian Journal of Medical Research, 127 (4). pp. 388-394. ISSN 0971-5916
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Abstract
Background & objectives: Activation of T cells is mediated through two critical signals provided by activated macrophages. The first signal is triggered when T cell receptor (TCR) binds to the major histocompatibility antigen (MHC/Ag) complex. The second signal is the interaction of co-stimulatory molecules with their respective ligands on T cells for their activation and proliferation. We undertook this study to observe the modulation in B7.1 (CD80) and B7.2 (CD86) co-stimulatory molecules on Mycobacterium tuberculosis infected monocyte derived macrophages (MDM) and their role in T helper (Th1) cell apoptosis. Methods: M. tuberculosis clinical strains (S7 and S10) and laboratory strains (H37Ra and H37Rv) were used to infect the MDMs. The modulation of apoptosis was assessed by treating T cells with anti-CD3 and anti-CD28 antibodies. The infected MDMs were co-cultured with autologous PPD pulsed T cells to ascertain the role of co-stimulatory molecules during infection. Results: In infected MDMs, all strains on day 1 but only S7 on day 2 showed significant decrease (P<0.05) in B7.1 expression compared to uninfected. The expression levels of B7.2 were also low on day 1 in S7, S10 and H37Ra infected MDMs. The anit-CD3 induced apoptosis in PPD pulsed Tcells showed further reduction with anti-CD28 antibodies. However, the modulation observed in B7.1 expression in infected MDMs was not reflected in T cell apoptosis in co-culture experiments. Interpretation & conclusions: Our results confirmed the role of B7.1 in rescuing the activated Tcells from undergoing apoptosis. During infection when the expression of B7.1 is downregulated, other co-stimulatory molecules may take over its crucial role to confer protective immune response against M. tuberculosis.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | Apoptosis - B7.1 - B7.2 - co-stimulation - Mycobacterium tuberculosis |
| Subjects: | Tuberculosis > Laboratory Research Tuberculosis > Laboratory Research > Immunological Tuberculosis |
| Divisions: | Basic Science Research > Immunology |
| Depositing User: | Dr. Rathinasabapati R |
| Date Deposited: | 01 Jun 2017 11:13 |
| Last Modified: | 01 Jun 2017 11:13 |
| URI: | http://eprints.nirt.res.in/id/eprint/877 |
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