BIO 343 Lecture Notes - Lecture 13: Pneumocystis Pneumonia, Dendritic Cell, B Cell
Immunology Chapter 13: Failure of the Body’s Defenses
Hayden Casassa
• Most iuodefiie’s ae auied ad ot pia
• 5 gay men in LA were diagnosed with Pneumocystis carinii pneumonia
o 1.1 million in the US living with HIV, 700,000 have died
o 1 in 7 are unaware
• Acquired Immune Deficiency Syndrome (AIDS) is caused by Human Immunodeficiency Virus
o Primary cell infected is CD4 T helper cells
o Macrophages and dendritic cells which also express CD4 are infected
o Opportunistic pathogens is what kills patients
o HIV was spread from primates to humans
o Most new cases and deaths were in Sub-Saharan Africa
o Most tasissios ee ale to ale… seod as seual otat ith ko ifetio
• What increases your risk of HIV?
o IV Dugs… seuall atie… postitute… eo ith HIV+ mother
• HIV has cone-shaped nucleocapsid consisting of the viral genome and the enzymes Protease, Integrase,
and Reverse Transcriptase
• HIV is an enveloped Retrovirus (RNA virus) whose genome consists of two identical RNA molecules
o Viral Reverse Transcriptase→ converts viral RNA into single-stranded cDNA then dsDNA
▪ Known as an error prone enzyme
o Integrase → inserts dsDNA into host DNA
▪ Once viral genome is integrated in host, it is called a Provirus and remains latent
o Protease → cleaves a polyprotein called gp160 into gp41 and gp120
▪ Polyprotein is large protein that is cleaved to smaller ones
o Gp120 → attachment protein that binds to CD4 and a co-receptor
o GP41 → anchors gp120 in host membrane and aids in fusion
• Transmission
o Typically bodily fluids (not saliva or kissing)
o Provirus can be carried by CD4+ T cells or by dendritic cells, or macrophages
o Virus particle can be transmitted via blood
o Most infections take place across mucosal surfaces
• Gp ids to CD ad to eithe CCR o CXCR, hih ae heokie o-eeptos euied fo
viral entry
• HIV Co-receptors are chemokine receptors
o Cheokies ae a lage goup of sall poteis ioled i guidig WBC’s to ifetio site
▪ CCR5→ expressed by dendritics, macrophages, and CD4 cells
▪ CXCR4→ expressed by activated T cells
• Two major variants of HIV. The cells they infect depends on which co-receptor they bind
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