B cells and Antibodies Flashcards
NK cells function:
Kills infected cell (part of innate)
B cell
Neutralization of microbe though phagocytosis, complement activation
Helper T cell
Activates macrophages; helps with inflammation;
of T and B lymphocytes
Cytoxic T cells
Kills infected cells
Regulatory T cells
Repress immune response
What is a naive B Cells?
Mature B cells that have no encountered their antigen..
What is required for immunoglobulin secretion
B cell must interact with antigen + CD4 Helper T cell
Antibody functions:
Neutralization, opsoniziation, complementation activation which can induce inflammation.
Antibody isotype switching maintains same what?
Same variable region. Only effects Fc portion (on heavy chain only)
Naive B cells contain what antibody type?
IgM and IgD
How do cells class switch?
CD40/CD40 ligand (on T cell) is required for class swtching. Also, T helper cells dictate the isotype selected via cytokines.
IgM
- Pentamer (when secreted). Monomers linked by disulfide bonds and J chain
- confined to blood stream; 10 binding sites.
- Predominant during first week of infections.
- Good at complement activation
IgG
- Most abundant in serum
- crosses placenta; provides protection in babies
- opsonin, activates complement, neutralizes toxins.
IgA
- located mostly in mucosa
- Sero-mucous secretions (breast milk, colostrum, tears, saliva)
- Dimeric structure at mucosa (linked via J chain)
- Monomer in serum
- Mainly a neutralizing antibody
- Will be secreted into lumen of GI usually with secretory component still attached.
IgE
- monomer
- low levels in serum
- induced by parasites
- important in allergic reactions
- binds to Fc receptors on mast cells, basophils, esoinophils independent of antigen
- When antigen binds it, it will trigger granules to release and induce inflammation.
