The present study focuses on understanding the reasons for immune dysfunction in lung cancer (LC) patients and understanding role of cyclooxygenases (COX) inhibitors in modulating anti-tumor immunity. Lymphocytes of LC patients showed decreased proliferation when stimulated with mitogens, decrease in calcium flux, low expression of activation markers and low cytotoxic response with high generation of reactive oxygen species. These lymphocytes exhibited a marked decrease in IFN- and high IL-10 with decrease in transcription factor T-bet and increased expression of GATA-3.

T-cell Acute Lymphoblastic Leukemia (T-ALL) is a clonal lymphoid malignancy. The present project aimed at determining the incidence of clonal TCR  and  junctional gene rearrangement status in Indian T-ALL patients at diagnosis and analyzing the suitability of clonal TCR  and  junctional gene rearrangement status at diagnosis as a prognostic marker for T-ALL.

Alkylamines are the group of non peptidic molecules, which are capable of stimulating Vγ9/Vδ2 T cells. These alkylamines are secreted at millimolar concentrations in bacterial culture supernatants and also are found at high concentrations in tea and at lower concentrations in other edible plant products such as apples and wine. Our studies demonstrate, ethylamine in combination with cytokines IL-15 is able to activate γδ T cells. Activated γδ T cells express activation markers (CD69 and CD25) and chemokines receptors (CCR5 and CXCR4).

 Immunosuppression appears to be more frequent and more profound in patients with head and neck cancer. The immune impairment often observed in these patients is not restricted to the tumor site but presents itself as a systemic defect. The project aims at understanding the molecular mechanism of CD3 ζ chain degradation, both at the mRNA and protein level. Studies demonstrate a marked reduction in lymphocyte proliferative responses, calcium flux and a strong TH2 bias in OC patients.

The present project aims at understanding the role of Toll like receptors (TLRs) and regulatory T cells in modulating the anti tumor immunity mediated by γδ T cells in patients with oral and cervical cancer. Preliminary work demonstrated the presence of TLRs (TLR2, TLR3, TLR4 and TLR9) on γδ T cells from freshly isolated peripheral blood leucocytes (PBLs). γδ T cells were immunomagnetically purified from ex-vivo expanded PBLs and stimulated in the presence of a TCR stimulus (IPP and anti-CD3) or a TLR stimulus (Poly I:C) or both in combination.

We are currently interested in analyzing the non-peptidic ligands recognized by γδ T cells on tumor cells. Our studies demonstrate that T lymphocytes expressing the Vγ9/Vδ2 TCR recognize non-peptidic phosphorylated compounds, their synthetic analogs bisphosphonates and endogenous metabolite Isopentenyl pyrophosphate (intermediate metabolite of mevalonate pathway) in tumor cells. γδ T cells release IFN-gamma and TNF-alpha after co-culture with a panel of oral, breast and prostate tumor cell lines as against lowered cytokines in normal, non-transformed cell lines.

γδ T cells play an important role as anti-tumor effector cells. However, their expansion is self-limiting. We investigated the activation induced cell death in γδ T cells after stimulation with heat shock proteins (hsp60, hsp70) that act as ligands for γδ T cells. Characterization of the molecular events in the apoptotic pathway revealed that nitric oxide (NO) is released by γδ T cells after hsp stimulation. Purified γδ T cells when incubated with rhsp60 and rhsp70 as well as artificial NO donors - SNAP and arginine, exhibited changes in mitochondrial membrane potential.