Question

Upon encountering an appropriate MHC Class I on an infected cell: Select one: a. naive T1 cells secrete cytokines b. TH1 cells differentiate into Th2 cells O c. CD8 cytotoxic cells destroy the infected cell O d . CD4 T cells release IL-4 e. BCRs become cross linked and signaling occurs

Answer 1

1 question

MHC is divided into class l and class ll. MHC class l protein are a part of immune system. They help to display the peptide bonds of a protein in the cell to cytotoxic T cells. T cells recognises healthy cell and do not show any immune responses. But when a foreign cell is displayed by MHC class l the CD8 cytotoxic cells attack the foreign cell and destroys it.

MHC class ll cells activate the helper T cells (Th cell) or CD4.

So the answer is option (c)

2 question

Natural killer cells are cytotoxic lymphocytes. These cells directly kill the infected cell without need for activation.

NK cells express CD 16 and CD57. They do not express CD3.

SO the answer is option (c)

3 question

The positive and negative selection of thymocyte helps to eliminate the unhealthy thymocyte cells.

A Double-negative thymocytes initiate rearrangement at the β, γ, δ locus (loci) before all other T cell receptor genes.

So the answer is option (e)