Diseases of Immunity 2 Lecture Flashcards
Define immunodeficiency
State where the immune system is incapable of defending the body from infectious disease
What is inherited (primary) immunodeficiency?
Hereditary
Affects both innate and adaptive (humoral and cellular) immunity
Autosomal recessive
Susceptible recurrent infections from 6-24 months
What is acquired (secondary) immunodeficiency?
Complications of infections Malnutrition Aging Side effects of immunosuppression Irradiation/chemotherapy for cancer
Diseases of inherited immunodeficiency may affect?
Specific immunity mediated by B and T cells
Non specific defense mechanisms mediated by complements, phagocytes, and NK cells
What is X-linked (Bruton’s) Agammaglobulinemia?
Example of a B cell defect
X-linked (more males than females)
Mutation in btk
Failure of B cell precursors to develop into mature B cells
Apparent after 6 months
No or little circulating B cells –> little or no ciculating antibodies infections of respiratory tract
Autoimmune diseases occur with increased frequency
What is the treatment for X-linked (Bruton’s) Agammaglobulinemia?
Replacement therapy with immunoglobulins to provide passive immunity
Antibiotics can be used
What is DiGeorge Syndrome (Thymic Hypoplasia)?
Example of T cell defect
Hypoplasia (or lack) of the thymus (failure of development of the 3rd and 4th pharyngeal pouches which give rise to the thymus)
Lack of T cell mediated immunity (poor defenses against viral and fungal infections)
Deletion of genes
Define SCIDs
Heterogeneous group of inherited disorders all having defects in both humoral and cell mediated immune responses
Those with SCIDs are susceptible to what and are treated through what?
All infectious pathogens (recurrent infections)
Bone marrow transplantation and gene therapy
What is transient acquired immunodeficiency?
Poor nutrition
Stress
Chemotherapy/immunosuppresive therapy
What is permanent acquired immunodeficiency?
HIV infection –> development of AIDS
What is AIDS?
Caused by retrovirus HIV
HIV 1 (RNA genome — gag, pol, and env genes – proteases) and 2
Profound immunosuppression (primarily of cell mediated immunity, which leads to infections)
Reduction of CD4+ T cells
Infects macrophages and dendritic cells
What is the treatment of AIDS?
Anti-retroviral drugs that target viral reverse transcriptase, protease and integrase
Highly active antiretroviral therapy (combination antiretroviral therapy –> avoid development of resistance)
HIV 1 Structure details?
RNA Reverse transcriptase (RNA --> dsDNA) Integrase (HIV into host genome) Protease Capsid: protein coat p17 matrix: middle coat Lipid coat: comes from the host cell 2 glycoproteins 120 and 41: host cell infections
How does virus enter into host cells?
Comes in via mucousal membrane
Only interacts with CD4 containing cells
gp120 attaches to CD4 and to co-receptor (chemokine – CCR5) after a conformational change
Once it bound, a conformational change occurs again and it binds to gp 41 (transmembrane glycoprotein)
gp41 inserts into the membrane leading to the fusing of the membrane of the virus and the host which leads to injection of the viral RNA
Then reverse transcriptase converts RNA to cDNA (ds)
Goes into the nucleus and ingrates via integrase and can stay there for years (latent virus)
