immune system lecture 2 Flashcards
name the inaccurate responses of the immune system
- Inadequacy to protect the host (immunodeficiency)
- Overexpression to a substance or hypersensitivity reactions
- Transfusion or transplantation reactions (alloimmunity)
- Reacting to the host’s own cells (autoimmunity)
immunodeficiency
inadequacy to protect the host
alloimmunity
transfusion or transplantation reactions
autoimmunity
reacting to the host’s own cells
primary immunodeficiency
- reflects a defect involving T cells, B cells, or lymphoid tissues.
- inherited defects in genesis of immune system
[complement proteins, phagocytes]
secondary immunodeficiency
results from an underlying disease or factor that depresses or blocks the immune response
[ex. chemo, aging, infection]
AIDS three main avenues
a) Contaminated blood
b) Sexual activity (anal, vaginal, very rarely oral)
c) Maternal to child (either through pregnancy, during delivery, or breastfeeding)
what type of HIV causes the global epidemic bc its more transmitted?
HIV-1
HIV
ribonucleic acid (RNA) virus, also known as retrovirus.
-the core contains glycoprotein spikes
HIV predominantly affects:
- CD 4 lymphocytes + helper cells
- macrophages and B cells
how long does the acute infection phase of AIDS last?
1-6 weeks with flu like symptoms and lymphadenopathy
asymptomatic year range
1-20 years, positive antibody test but no symptoms
seroconversion
the emergence of HIV antibodies in bloodstream
HIV treatment
1) do not cure HIV but aim to prolong lives of ppl with HIV
2) combo of medicines aim to stop HIV from turning into AIDS
3) medicines can reduce the risk of HIV transmissibility to other ppl
Type I hypersensitivity - IgE
-Mast cell (or basophil) releases histamine (via degranulation) that induces constriction of vascular and nonvascular smooth muscles, causing vasodilation and increasing venule permeability.
- depends of IgE that is formed into CD4+ that binds to mast cell and basophil
antihistamine
competing with histamine
type II hypersensitivity - tissue specific
IgM and IgG
- - symptoms and reactions depend on what organ express particular antigen
ex. graves disease, insulin resistant diabetes
type III - immune complex mediated
*IgG, IgM, IgA
- involves interaction of antibody and complement, which may attract the polymorphonuclear cells or neutrophils.
*kidneys, joints, and blood vessels are the most common tissues affected, lupus is an example
TYPE IV HYPERSENSITIVITY
(CELL-MEDIATED IMMUNITY)
*presence of T lymphocyte - mediated reactions
- delayed type of hypersensitivity reaction [latex, cosmetics reaction]
- ex. graft rejection, allergic reaction after receiving transplantation
autoimmune diseases
➢Immune mechanisms directed against self-antigens
▪ The body fails to distinguish self from non-self, causing the immune system to direct immune responses against normal (self) tissue and become self destructive.
Immunologic tolerance
The unresponsiveness of certain antigens induced by their exposure to lymphocytes.
Self-tolerance
Lack of recognition and responsiveness to one’s own tissue antigens.
Autoimmunity indicates…
loss of self-tolerance
central tolerance
- Immature lymphocytes that recognize self-antigens during their maturation in central (generative) lymphoid organs are killed by apoptosis.
peripheral tolerance
Mature lymphocytes that recognize self-antigens become either anergic (i.e., functionally inactive) or suppressed by regulatory T cells or undergo
apoptosis.
LUPUS ERYTHEMATOSUS
chronic inflammatory autoimmune disorder that appears in several forms
Discoid lupus erythematosus
only affects the skin [face,neck,scalp]
Systemic lupus erythematosus
can affect any organ or system in the body
isoimmune disease
Transplantation of almost any tissue is feasible, but the clinical use of transplantation to remedy disease is still limited for many organ systems because of the rejection reaction
*cause is incompatibility of cell surface antigens, surface HLA proteins of the donor’s tissue are different from the recipient’s.
