Immune Response to HIV Immune Response to HIV InfectionInfection

June 28, 2001June 28, 2001

Ms. Jane Coyle-MorrisMs. Jane Coyle-Morris

Wyeth-Ayerst ResearchWyeth-Ayerst Research

Immune Response to HIV Immune Response to HIV InfectionInfection

ImmunologyImmunology HIV BiologyHIV Biology Immune Response to HIV InfectionImmune Response to HIV Infection

Role of Antibodies

Antibody interaction with Complement Proteins

Cytotoxic T-Cells

Central Role of Helper T-Cells

Macrophage

Large, irregularly-shaped phagocytic cells that act as the body’s scavengers. Macrophages engulf and consume foreign material such as bacteria and viruses.

T CellsT Cells

Arise from stem cells in the bone marrow then migrate to the thymus gland where they develop the ability to recognize foreign antigens in a specific manner.

Helper T Cells (THelper T Cells (THH))

Detect infection and initiate both humoral and cell-mediated responses (CD4 cells)

Cytotoxic T Cells (TCytotoxic T Cells (TCC))

Recruited by TH to lyse infected body cells (CD8 cells)

Cell Marker ProteinsCell Marker Proteins

CD4: cell marker found on the CD4: cell marker found on the surface of Tsurface of TH H and macrophages; and macrophages; acts as a receptor for HIVacts as a receptor for HIV

CD8: cell marker found on the CD8: cell marker found on the surface of Tsurface of TCC

B Cells and Plasma CellsB Cells and Plasma Cells

B Cells: precursors of B Cells: precursors of plasma cells, specialized plasma cells, specialized to recognize particular to recognize particular foreign antigensforeign antigens

Plasma Cells: derived Plasma Cells: derived from B cells, they from B cells, they produce antibodies to produce antibodies to specific antigens specific antigens marking them for marking them for destructiondestruction

Major Histocompatibility Major Histocompatibility Complex (MHC)Complex (MHC)

Proteins markers found on the Proteins markers found on the surface of the body’s cells to signal surface of the body’s cells to signal “self” from “non-self”. MHC-I can “self” from “non-self”. MHC-I can be found on every cell in the body be found on every cell in the body while MHC-II is found only on B while MHC-II is found only on B cells, T cells and macrophages.cells, T cells and macrophages.

CytokinesCytokines

Soluble proteins secreted by the cells of Soluble proteins secreted by the cells of the immune system to signal activation the immune system to signal activation and proliferation of the appropriate and proliferation of the appropriate components of the immune response. IL-components of the immune response. IL-1 is released from macrophages and 1 is released from macrophages and signals activation of T cells. Activated T signals activation of T cells. Activated T cells produce IL-2 which signals cells produce IL-2 which signals proliferation of T cell clones and also proliferation of T cell clones and also helps B cells to start secreting antibodies.helps B cells to start secreting antibodies.

CytokinesCytokines

The Immune ResponseThe Immune Response

Central Role of CD4 T CellCentral Role of CD4 T Cell

HIV BiologyHIV Biology

HIV in ActionHIV in Action

Natural Course of HIV Natural Course of HIV InfectionInfection

OverviewOverview

Immune Response to HIV Immune Response to HIV InfectionInfection

ImmunologyImmunology: humoral vs. cell-: humoral vs. cell-mediatedmediated

HIV biologyHIV biology: complex series of events : complex series of events leading to viral entry and course of leading to viral entry and course of infection; evasion of immune systeminfection; evasion of immune system

Immune response to HIVImmune response to HIV: weak : weak humoral response, strong cell-humoral response, strong cell-mediated response diminished over mediated response diminished over time by depletion of helper T-cellstime by depletion of helper T-cells

AIDS/HIV Internet SitesAIDS/HIV Internet Sites

Www.ama-assn.org/special/hiv/Www.ama-assn.org/special/hiv/hivhome.htmhivhome.htm

www.planetq.com/aidsvl/index.htmlwww.planetq.com/aidsvl/index.html www.thebody.com/cgi-bin/body.cgiwww.thebody.com/cgi-bin/body.cgi www.cdc.gov/www.cdc.gov/ www.pbs.org/wgbh/nova/aids/www.pbs.org/wgbh/nova/aids/ www.roche-hiv.com/default.htmwww.roche-hiv.com/default.htm