Question

1.1 What occur within 4 hr of a pathogen first breaching anatomic barriers (select all that apply)? a. Activation of complement b. Defensins are released c. Release of Histatins d. Activation of T-cells e. Lysozyme digestion of bacterial cell walls

1.2 what cell type of the innate immunity is primarily responsible for dealing with intracellular pathogens (select one)? a. Mast Cells, b. B-cells, c. Neutrophils, d. Macrophages, e. Natural Killer cells

Answer 1

1.1

Answer : A and B

Lysozyme digestion of bacterial cell wall and release of histatins occur in the saliva by salivary gland which comes under anatomical barriers. lysozyme is also found in tears and in mucus.

After breaching the anatomic barriers , our body defense of innate( internal defenses) occur which include inflammatory response from mast cells and basophils,natural killer cells, activation of complement and phagocytosis by monocytes, macrophages and neutrophils. Defensins are produced by circulating white blood cells and found in neutrophils and macrophages.

Then adaptive immunity consisting of activation of T cells and B cells occur .This is the final line of defense. Activation of T cells take place within 4-6 days . They get activated when they are presented with peptide antigens by MHC class ii molecules and then they secrete cytokines to support the immune system.

1.2

Answer : D

Macrophages are the cells of innate immunity which are primarily responsible for dealing with intracellular pathogens. T helper cells activate macrophages and this activated macrophages fuse their Lysosome to phagosomes efficiently to present the intracellular pathogens to lysosomal enzymes that are microbicidal. Cytotoxic T cells destroy this pathogens by releasing perforins or by inducing apoptosis of infected cells.