Lecture 17 Flashcards
Ch 13 failures of the body's defenses
Define immunodeficiency.
Failure to protect the host from pathogens or malignant cells
Vaguely explain the difference between a primary and secondary immunodeficiency.
Primary- genetic and/or present at birth
Secondary- results from exposure to various agents… acquired
What happens to the innate immune response in a primary immunodeficiency?
Defects occur in the following: neutrophils, phagocytes, and complement, leading to increased susceptibility to bacterial infections
A phagocyte defect increases susceptibility to what type of infections?
Extracellular bacteria and fungi
A complement defect increases susceptibility to what type of infections?
Extracellular bacteria, specifically Neisseria spp
What happens to the adaptive immune response with a primary immunodeficiency?
B and T lymphocytes cannot be properly developed and activated
What is the result of a deficiency in T lymphocytes?
SCID
What is it called when there is an MHC class I or MHC class II deficiency?
Bare lymphocyte syndrome (because no CD8 or CD4 T cells can be activated)
What are some of the defects in cell interaction and signaling between a B cell and T cell?
Defects in: JAK-3 pathway, RAG enzymes, expression of MHC class II, bruton’s tyrosine, gamma chain of receptors for IL-2
What is X-linked agammaglobulinemia?
It is a primary immunodeficiency where the patient has no gamma globulin, a major Ab fraction of serum, leaving them with few to no mature B cells. It is found on the X chromosome and is therefore X-linked, affecting mostly males.
How does X-linked agammaglobulinemia prevent B cell maturation?
Without btk present, phospholipase C cannot activate, and there are no second messengers of DAG and IP3 which prevents maturation of a pro to pre B cell.
How does X-linked agammaglobulinemia function in a female carrier?
Since a female has two X chromosomes, she can either be a carrier or have her B-cell development arrested. If the defective X is inactivated, then signaling and maturation will be normal, as opposed to the normal X being inactivated, which would cause the disease.
In normal infants, what Ab is transiently deficient in the first year of life?
IgG
What are two ways secondary immunodeficiencies can occur?
Malnutrition and agent-induced immunodeficiency
What is affected by malnutrition?
Cell-mediated immunity is affected
What are some examples of agent-induced immunodeficiencies?
Exposure to chemicals, corticosteroids, immunosuppressive drugs for transplant patients, or radiation/chemotherapy for cancer patients
What causes AIDS?
An infection of HIV-1
How was the first group of patients diagnosed with AIDS?
Group of patients shows a rare fungal pathogen, had Kaposi’s sarcoma, and decreased CD4+ cell populations
During the global AIDS epidemic, who was affected more: males or females?
Males
People living with HIV has increased or decreased over the years?
Increased
How can HIV be transmitted?
Hetero or homosexual intercourse, recipients of infected blood, and passage from mother to infants
Why would anal intercourse be more likely for infection versus vaginal intercourse?
Microtears/bleeding occurs more easily in the anus than in the vagina
In Eastern Europe, what is the biggest mode of HIV transmission?
IDU (intravenous drug use)
Name at least one prevention intervention of HIV.
Hint: you probably have seen an ad for one on TV
- pre-exposure prophylaxis
- vaginal and rectal microbicides
- post-exposure prophylaxis
- male condom use
- male circumcision
