Describe two different ways in which infection with bacteria or viruses compromises T-cell tolerance, leading to the production of effector T cells specific for self antigens

Question

What will be an ideal response?

Answer 1

(i) Inflammatory cytokines induced by infection can activate autoreactive T cells nonspecifically, and interfere with the ability of regulatory T cells to maintain peripheral tolerance.
(ii) T-cell cross-reactivity can occur when pathogen peptides have related amino acid motifs compared with self peptides and, when bound to the same or similar MHC allotype, can lead to the activation of self-reactive T cells. In some cases the only requirement is a common peptide:MHC structural conformation and neither peptide nor MHC relatedness is actually required. In both cases, however, molecular mimicry is operating.