Jitt # 9 Case Study Infectious Mononucleosis

Question 1

What T cell subset is activated to combat against pathogens that replicate inside organsims (specifically phagosomes)?

Answer 1

CD4 Th1 cells activate macrophages to release antibacterial agents into vesicles (phagosomes) to eliminate pathogens.

Question 2

When the cytosol of an organism is infected with pathogen, what is the immune response?

Answer 2

The infected cell is destroyed. This is mediated by CD8 T cells in adaptive immunity and NK cells of innate immunity

Question 3

What are the two enzymes released by CD8+ to induce apoptosis?

Answer 3

1) Fragmentins (granzymes), which induce apoptosis # 2) Perforin, acts as a translocator, pore forming protein to enable granzymes to cross the membrane of the target cell.

Question 4

What is Fas, and how does it relate to adaptive immunity?

Answer 4

The Fas ligand is bound on the membrane of CD8 T cells as well as on some CD4 T cellsm and induces apoptosis by binding Fas on a limited range of target cells.

Question 5

What is IFNg’s role in CD8 immunity?

Answer 5

IFNg is secreted by CD8 cells, which inhibits viral replication, induces MHC I expression, and activates macrophages

Question 6

Symptoms of EBV infection

Answer 6

Severe pharyngitis; petechiae on palate; swollen lymph nodes (neck); enlarged liver and spleen; large numbers of atypical lymphocytes;

Question 7

Downey-McKinlay cells

Answer 7

also known as mononucleocytes; large cells with foamy basophillic cytoplasm and fenestrated nuclei; control the acute infection by destroying EBV- infected B cells; mostly from the CD8 lineage

Question 8

What type of cells does EBV infect? How does it enter these type of cells?

Answer 8

EBV enters B cell by binding to the B-Cell surface molecule CD21 (Complement receptor 2 (CR2))

Question 9

CD21

Answer 9

Complement Receptor 2 (CR2) Present on the surface on B cells and acts as a receptor for complement fragment C3dg; also present on various types of epithelial cells in the nasopharynx, parotid gland duct, female cervix, and male urethra.

Question 10

How do we test for EBV infection?

Answer 10

The presence of EBV specific IgM antibodies “heterophile antibody” against EBV capsid antigen (VCA)

Question 11

mitogenic

Answer 11

substances that encourage cellular division.

Question 12

BCRF-1

Answer 12

Viral gene; encodes for the protein BCRF-1 aka vIL-10, which is very similar to IL-10 in humans; BCRF-1 is mitogenic.

Question 13

EBV infection causes the release of what cytokines?

Answer 13

IL-10, IL-6;

Question 14

IL-10 and EBV infection

Answer 14

IL-10 activates B cells and inhibits T cell production of IL-2 and IFN g; also enhances the production of B-cell stimulatory cytokines such as IL-4.

Question 15

IL-6 and EBV infection

Answer 15

EBV infection causes increased release; IL-6 may inhibit the ability of NK cells to destroy EBV infected cells.

Question 16

What consequence does increased B cell proliferation have on immunity?

Answer 16

Increased self reactive B-lymphocytes; autoimmune manifestations.

Question 17

EBNA-2

Answer 17

EB Nuclear antigen 2. critical for transformation of B cells;