People who are Δ32 homozygous for the deletion are highly resistant to HIV, while heterozygotes are partly resistant.

TLS Online TPP Program

#Id: 7480

#Unit 4. Cell Communication and Cell Signaling

IgA is the principal class in secretions, the most important being those from the epithelia lining the intestinal and respiratory tracts.

Dimeric IgA operates mainly on epithelial surfaces.

This monomeric IgA is predominantly of the subclass IgA1; the ratio of IgA1 to IgA2 in the blood is 10:1.

IgA antibodies produced by plasma cells in the gut are dimeric and predominantly of subclass IgA2; the ratio of IgA2 to IgA1 in the gut is 3:2.

TLS Online TPP Program

#Id: 7481

#Unit 4. Cell Communication and Cell Signaling

IgE 

Present only at very low levels in blood or extracellular fluid but is bound avidly by receptors on mast cells.Antigen binding to this cell-associated IgE triggers mast cells to release powerful chemical mediators that induce reactions such as coughing, sneezing, and vomiting.

TLS Online TPP Program

#Id: 7482

#Unit 4. Cell Communication and Cell Signaling

IgD

B cell antigen receptor and may participate in B cell maturation.Exact function is still unclear, IgD may be involved in humoral immune responses by regulating B cell selection and homeostasis.

TLS Online TPP Program

#Id: 7483

#Unit 4. Cell Communication and Cell Signaling

Function of antibody 

TLS Online TPP Program

#Id: 7484

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 7485

#Unit 4. Cell Communication and Cell Signaling

Antigenic Determinants