Biology Test Immunology 3

Question 1

Which cells are considered the 'professional' antigen-presenting cells (APCs) most efficient at activating naive T cells?

Accepted Answer

Dendritic cells

Answer

Dendritic cells are the most potent professional APCs because they express high levels of MHC molecules and co-stimulatory signals needed to prime naive T cells.

Question 2

What is clonal deletion in the context of T cell development?

Accepted Answer

Elimination of self-reactive T cells in the thymus

Answer

Clonal deletion is the process in the thymus where T cells with high affinity for self-antigens undergo apoptosis during negative selection.

Question 3

Which antibody isotype is most abundant in mucosal secretions such as saliva and breast milk?

Accepted Answer

IgA

Answer

Secretory IgA (sIgA) is the predominant antibody in mucosal secretions and provides first-line defense at mucosal surfaces.

Question 4

What does the term 'somatic hypermutation' refer to in B cell biology?

Accepted Answer

Targeted mutations in immunoglobulin variable regions to increase antibody affinity

Answer

Somatic hypermutation introduces point mutations in the variable regions of immunoglobulin genes, allowing for the generation of B cell clones with higher antigen affinity.

Question 5

Which pattern recognition receptor is responsible for detecting lipopolysaccharide (LPS) from gram-negative bacteria?

Accepted Answer

TLR4

Answer

TLR4 (Toll-like receptor 4) recognizes LPS from gram-negative bacterial cell walls, triggering innate immune responses.

Biology Practice Test

Biology Practice Test

Biology Test Immunology 3