microbiology unit 3 exam

Substance against which the immune response occurs. Proteins and carbohydrates

(epitopes) ....part of antigen targeted by immune response.

surface receptors that will bind to it. 

Cell Mediated Immunity (CMI)

• T helper cells. Ex. CD4+
• T cytotoxic cells. Ex. CD8+

Antigen Presentation. Antigen Presenting Cells (APSs)-Macrophages and dendritic cells.

• phagocytize and digest antigen. Fragments(potentialADs) are displayed on cell surface and bound to a MHC protein.
• T cells bind to displayed ADs.

• MHCII plus AD displayed on APC.
•    Undergo cell division. Large popluations of cells targeted to antigen proven to be a threat. –Several active types of TH cells and memory TH
•    Secrete cytokines. 

required for activation of T_C , B cells and several other types of cells.

–TCs bind to MHC-I plus AD displayed on APC

–Cytokines from activated TH cells

•Activation Results

–Cell division

• •Larger population of activated cells (CTL’s) targeted
• to current threat.

•Memory

• •B cells become programmed to respond to a particular antigenic
• determinant.

• –Produce proteins called antibodies (immunoglobulins) that
• specifically bind to that antigenic determinant.

–B cell is activated

• •Cell division creates a large population of B cells
• that target this AD

–Some form the memory for this AD

• –Some become plasma cells that secrete antibodies
• targeted to this AD

•B cell binds to antigen and presents AD.

•TH binds to presented AD and secretes  cytokines.

• •Effects of antibodies binding to their ADs.  (formation of antigen-antibody
• complexes) 

–complement activation (classical pathway)

• –opsonization (Fc region binds to
• phagocytes)

• –agglutination (inactivation &/or increased
• efficiency of phagocytosis)

–neutralization (toxins, viruses)

–antibody-dependent cell-mediated cytotoxicity

–*know the bold words in the next slide*

• - large pool of cells programmed for this AD -
• some can immediately become plasma cells
• –rapid increase in titer prevents significant increase
• in number of microbes so no illness 

•Antibody Kinetics

• –Primary Response - first exposure
• to AD

• •7 - 10 days for rise in titer due
• to time needed for T and B cells to proliferate

• –time for microbe to grow and
• disease symptoms to appear

Secondary (Anamnestic) Response - subsequent exposure to AD

during primary reponse. rapid response by these cells to subsequent infections.