immunology 3: adaptive, lecture 16

Cell-mediated response

• each T cell= 1 type of antigen

  1. antigen- presenting cells(APC) show helper T cells the antigen

  2. Helper T cells activate B cells AND cytotoxic killer T cells

  3. Cytotoxic killer T cells kill cells that are acting abnormal due to infection oof cancer

     • check the “ID badge” for every cell in body called HLA(human leukocyte antigen)

     • The ID badge displays bits of every protein the cell makes; if virus is inside, viral bits show up on the badge

     • Organ transplants reject because the “ID badge” doesn’t match

       4. When infection clears, regulatory T cells call things down, and small population stays behind as memory T cells

HIV/AIDS

• HIV(human immunodeficiency virus) is an enveloped retrovirus that uses revere transcriptase RNA-DNA

• Targets helper T cells, affecting both humoral and cell- mediated immunity

AIDS

• AIDS( acquired immunodeficiency syndrome) is the late stage of untreated HIV infection

• Normal helper T cells count= 500-1,500 cell/mm 3

• AIDS helper T cell count= less than 200 cells/mm3

• Opportunistic infections due to weakened immunity, TB, pneumonia, candidiasis

• Transmission: blood, semen, vaginal fluids, breast milk, transplacental

• NOT saliva or contact

HIV/AIDS treatment

• antiretroviral therapy(ART) allows people to live long, healthy lives

• PrEP( pre- exposure prophylaxis) and PEP) post/exposure prophylaxis)

• Undetectable=untransmittible

• Someone whose treatment keeps virus leveled undetectable does not pass HIV to sexual partners