Unit 3 - Formative 9 D1

Stem cell development into myeloid lymphoid progenitor cells

Myeloid cell development in the marrow

Myeloid progenitor cells into netrophils

Myeloid progenitor cells into monocytes

Myeloid progenitor cells into eosinophils

Myeloid progenitor cells into basophils, platelets and erythrocytes

Stimulate release of mature neutrohils stored in BM; increase hematopoietic growth factors causing an increase in differentiation of myeloid precursor cells

C: Large (blue); formed early in neutrophil maturation
MC: Myeloperoxidase (MPO)

C: Small (pink)
MC: Collagenase, plasminogen activator

Acute Myeloblastic Leukemia

MPO stain used to identify immature leukemic cells (called blasts) since myeloblasts stain positive for MPO

Cells can't form ROS (superoxides) to kill pathogens

1. Bacteria binds FcR or CR1
2. NADPH oxidase enzyme converts 02 to superoxide
3. Superoxide converted to H202 (can kill but not very efficient)
4. H202 converted to OH (effective)
5. OH +Cl -> HOCl (highly effective, bleach)

Produces HOCl from H202/OH and Cl; used by neutrophil granulocytes to kill bacteria

Only gp91 is located on cell membrane before cell stimulated; 3 other cytoplasmic components join to form functional NADPH oxide enzyme

NBT( nitro blue terazolium) dye + neutrophils
Drop of LPS to stimulate neutrophils, which take up dye and stimulator
Normal neutrophils form ROS and turn deep purple

Dihydrorhodamine (DHR) is reduced to fluorescent rhodamine in stimulated neutrophils if respiratory burst is intact
Fluorescence is measured by flow cytometry

Mutation in CD18 gene which encodes beta chain found in all B2 integrins (LFA-1)

Mutation in gene required for sialyl-Lewis X synthesis; pts get recurrent bacterial and fungal infections because their leukocytes have difficulty migrating to infection sites

B2 integrins also expressed on Tcells; (LFA-I (B2) binds w/ ICAM-1)
Also LFA-1 is used for migration of activated T cell to infection site

However, no recurrent infections SOLELY attributable to defects in T cell activation

Steps in leukocyte migration (endothelial cells at infection sites produce IL-8; leukocytes bind via integrins; leukocytes diapedese into tissues towards microbes

Activates macrophages to produce IL-1 and TNF-alpha
Increases production of nitric oxide (NO, microbicidal) by phagocytes

Increase production/release of phagocytes from BM
Increase expression of adhesion molecules on endothelial cells and production of chemokines (IL-8)

Structural proteins

p24: capsid protein
p17: matrix proteins

reverse transcriptase; produces dsDNA provirus -> proviral dsDNA integration into host DNA -> cleaves polyprotein

Reverse transcriptase: produces dsDNA provirus
Integrase: Proviral dsDNA integration into host DNA
Protease: Cleaves polyprotein

Surface protein that binds to CD4 on host cell responsible for tropism; genetic drift transmembrane protein for cell fusion

The virion structure

Simple: gag, pol, env genes
Complex: gag, pol, env, tat, rev, nef, etc

1. Acute
2. Latent; sublinical immune dysfunction
3. Progression to AIDs/systemic immune deficiency

Mechanism of Infection

1. Surface gp120 - CD4 of Th cells
2. HIV loses envelope, RNA uncoated
3. RNA copied using virion associated reverse transcriptase; dsDNA made
4. DNA and integrate into nucleus; DNA integrated into host DNA forming provirus (regulatory proteins determine rate of viral replication)
5. Transcription produces ss (+) RNAs
6. Translation produces proteins, assembly, maturation/release of virus

Progression

ELISA to detect HIV Ab in pts serum

Anti-p24 first reliably detected antbody but declines as viral titers rise later in infection; envelope ab rise more slowly but stay high at end (bc of major antigenic variation);

ELISA for p24 ag useful early

Western blot for ab specific to HIV (electrophoretically separated HIV antigens react with the pts ab; detection by enzyme labeled anti-human IgG or immunofluoresence

HIV DNA PCR