Virus infected cell is killed by -

Ans. is 'b' i.e., Macrophages "Protein in Toll family (TLR 1-9) can be expressed on macrophages, dendritic cells and B cells as well as on a variety of non-hematopoietic cell types including respiratory epithelial cell. Upon ligation, these receptors activate a series of intracellular events that lead to the killing of bacterial and virus infected cells as well as to the recruitment and ultimate activation of antigen-specific T and B lymphocytes". . Interferons do not kill the virus infected cells. They act on other cells of same species, rendering them refractory to viral infection.