Immunopathology of Infectious Diseases Continued Flashcards
What are some defects caused by pathogenic mechanisms?
Induction by physical means
Granulocyte and monocyte defects in movement, phagocytosis or killing or decreased number of cells (neutropenia)
Individual components of complement system
T cells (Di Georges Syndrome)
B cells (Brutons syndrome)
Combined Immunodeficiency (T and B cell ) pathogen
Immune Deficiency: Congenital and Acquired include what general categories?
Hereditary complement deficiencies
Defective phagocytes
Immune suppression
Consequences of hereditary complement deficiencies include deficiencies of what enzymes?
C1q, C1r, C1s, C4 and C2 are associated with defects in activation of the classic complement pathway
(defects lead to greater susceptibility to pyogenic staphylococcal and strep infections)
A deficiency in C3 in the complement pathway leads to what?
leads to defect in activation of both the classic and the alternative pathways, which also results in a higher incidence of pyogenic infections
A deficiency of the properdin factors of the complement pathway leads to what?
Impair activation of the alternative pathway predisposes to pyogenic infections
Deficiencies of C5 through C9 are associated with what?
with defective cell killing with increased susceptibility to disseminated neisserial infections
Consequences of deficiencies in the complement pathways. Factor B binds to C3b on cell surfaces and what happens?
Plasma serine protease D cleaves and activates B-C3b as part of the alternative pathway
What factors limit the inappropriate activation of complement?
Factors FI and FH
FH bins to C3b and prevents activation and is a cofactor for FI
FI is a serine protease that cleaves C3b and C4b.
What are some features of hereditary angioneurotic edema?
Genetic form of Angioedema, also called Qunike’s disease
Persons with it are born lacking C1 esterase inhibitor
Non-pitting edema
What is autoimmunity?
persons are tolerized to self antigens which prevents autoimmune disease
Deregulation of the immune response may be initiated by cross reactivity with what?
microbial antigens
ex: group A step or rheumatic factor
Polyclonal activation of lymphocytes induced by what?
tumors or infection
Ex: malaria, epstein barr virus infection
Autoimmune reactions result from the presence of what?
autoantibodies, activated T cells, and hypersensitivity reactions
Individuals with certain MHC antigens are at a higher risk for what?
autoimmune responses
ex: human leukocyte antigen, juvenile RA, ankylosing spondylitis
responses are associated with inflammatory TH1 type responses
Multiple sclerosis, an inflammatory response directed against myelin basic protein, may be triggers by what?
immune responses to one or more viruses, such as human herpesvirus 6 or measles
Systemic Lupus Erythematosus (SLE) is a chronic inflammatory autoimmune disorder may affect what?
organ systems
skin
joints and
internal organs
SLE may be mild or severe and life threatening, for most only a mild disease. What two categories of people are affected more then others?
African Americans and Asians
90% of individuals have discoid rash rather then ?
generalized SLE
Pediatric autoimmune neuropsychiatric disorders (PANDA) is associated with streptococcal infections. What are some examples of these disorders?
Describes children who have obessive compulsive disorder and/or tic disordres such as Tourette’s Syndrome
symptoms worsen following strep or scarlet fever
What is the mechanism for PANDA?
It is thought to be similar to that of rheumatic fevers know as syndenhams chorea or st.vitus dance
Immunosuppression therapy is important for reducing excessive inflammatory or immune responses of macrophages and T cells or for preventing the rejection of tissue transplants by T cells. Each card will go through the different immunosuppression treatments. 1. Anti-inflammatory treatments
Primarily target the production and action of TNF, IL-12 and IL-1
2nd immunosuppression therapy is Corticosteriods
Prevents their production by macrophages and may be toxic to T cells. Soluble forms of the TNF receptor and antibody to TNF can be used to block the binding of TNF and prevent its action
3rd is immunosuppression therapy for transplantation
generally inhibits the action or causes the lysis of T cells.
4th immunosuppression therapy is cyclosporin
tacrolimus and rapamycin prevent the activation of T cells. Anti-CD3 and antiCD25 prevent action of T cells to prevent a response
5th immnuosuppression therapy is antibody administation
to costimulatory molecules such as B7 or CD40 ligand at the time of transplant can block proper T-cell activation and promote anergy rather then responsiveness
Exotoxins are what?
Proteins that can produced by gram positive or gram negative bacteria and include cytolytic enzymes and receptor-binding proteins that alter a function or kill the cell
What are superantigens?
A special group of toxins that activate t cells by binding simultaneously to a t cell receptor and a major histocompatibility complex class II (MHCII) molecule on another cell without requiring antigen
Nonspecific means of activating T cells can trigger life threatening what?
Autoimmune like responses by stimulating the release of large amounts of interleukins, such as IL-1 and IL2
Superantigen stimulation of T cells can also lead to death of what?
the activated T cells causing the loss of specific T cell clones and their immune responses
Superantigens include what?
- -toxic shock syndrome of S. aureus
- -staphylococcal enterotoxins
- -erythrogenic toxin A or C of S. pyogenes
