Adaptive immune responses during Shigella dysenteriae type 1 infection: an in vitro stimulation with 57 kDa major antigenic OMP in the presence of anti-CD3 antibody.

An effort was made to understand the role of the 57 kDa major antigenic fraction of Shigella outer membrane protein (OMP) in the presence of T-cell antigen receptor in activation of adaptive immune responses of the cell mediated immune (CMI) restored patients. The expression of HLA-DR/CD4 out of CD3(+) T-cells was significantly dominant over the HLA-DR/CD8 and comparable to unstimulated cells of infected or healthy controls. CD4(+) T-cell activation together with HLA-DR is associated with the expression of CD25(+) (IL2Ralpha) for IL-2 growth factors with decreased IL-4 levels, required for maintaining the homeostasis of CD4(+) T cell. Furthermore, the positive expression of the CD45 antigen is possibly required for acquiring the memory for CD4(+) cells signals and facilitates the interaction with CD54 antigen. As a result, antigen-specific secondary signal is generated for B-cell activation to produce IgG2a and IgG2b. This suggests that antibody mediated-adaptive immune responses are generated due to anti-CD3 induced helper T-cell activity. The above mentioned findings reflect that the antigen alone might not exacerbate the selective T-cell responses. But these antigens in the presence of anti-CD3 antibody might help to elicit adaptive immune response via T-cell receptor (TCR) activation.