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Types of humoral immune responses and functional diversificiation of antibodies

1. review of
   • B cell functions
   • antibody functions
2. allergy
3. primary immunodeficiency diseases

this lecture

B cells process protein Ags and display them in the context of MHC II molecules to T cells

endocytosis of extracellular protein (takes it into MHC cell -> process it -> present peptide to T cell)

MAH class II: CD4 T cell

remember that when antigen 1st encounter - typically grabbed by antigen presenting cells, lie dendritic cells

load on MHC molecule -> specific for T cell -> present to T cell

this happens in B cells too

B cells present antigen (APCs) to T cells (Tfh) in the GCs

B cell recognition of native protein antigen

-> receptor mediated endocytosis of antigen

-> antigen processing and presentation

-> T cell recognition of antigen

B cells can see antigen independently,

Can internalize it, and activate T cell

B cells are antigen presenting cells

Interaction is only mechanism for antigen presentation to T cells during geminal center reaction

B cells are very good antigen presenting cells, and their presenting capability is required for last step in immune response, where B cells are left to interact for T cell immune responses

which immune cells present antigen to T cells during a T cell dependent Ab response?

pause for activity

1. dendritic cells - present antigen to initiate T activation
2. B cells - present antigen to already activated T cells

Ig heavy chain class (isotype) switching

went over this before

allergies

when the immune system attacks non-threatening substances

molecules involved in allergic reactions

IgE

• antigen binding sites in IgE antibody
• antibody constant region binds Fc receptors (FcRs) on innate cells
• FceR bind to the constant region of IgE. FceR receptors are present on mast cells

what antibody is the main receptor involved in allergic reactions?

IgE