Final Flashcards
HIV Replication
1-Virus attaches to the CD4 membrane receptor & sheds its protein coat, exposing its RNA core
2- Reverse transcriptase converts viral RNA into proviral DNA
3- The proviral DNA is integrated into the genome (genetic complement of host cell)
4- New virus particles are produced as a result of normal cellular activities of transcription & translation. Once the viral genome is integrated into host cell DNA, the potential for viral production always exists & the viral infection of new cells can continue.
5- New particles bud from the cell membrane
HIV Structure
Pol- produces DNA polymerase, produces endonuclease
Gag- codes for p24 & for proteins such as p17, p9, & p7
Env- codes for 2 glycoproteins, gp41 & gp120
HIV Type 1
Responsible for main AIDS epidemic, divided into 9 subtypes (Group M, N, O, P)
HIV Type 2
Endemic in parts of West Africa, strains have been classified into at least 5 subtypes (A-E), primary mode of transmission is via heterosexual contact
Reverse transcriptase
Enables the virus to convert viral RNA into DNA, this reverses the normal process of transcription in which DNA is converted to RNA, “retrovirus”
HIV Detection
Detection of HIV antibodies, antigens (particularly p24), detection or quantification of viral nucleic acid
HIV 1 antibodies detected by EIA
HIV antigen & genome testing
Type 1 Hypersensitivity Rxn
- Anaphylactic
- IgE antibody
- no complement involved
- Mast cells, basophils, granules (histamine)
- Cytokines involved
- Antibody mediated, immediate
- Allergic & anaphylactic reactions
- Anaphylaxis, hay fever, asthma, food allergy
Type 2 Hypersensitivity Rxn
- Cytotoxic
- IgG, possibly other immunoglobulins
- Complement involved
- Effector cells (macrophages, PMNs)
- No cytokines involved
- Antibody dependent; complement or cell mediated
- Target cell lysis; cell-mediated cytotoxicity
- Transfusion rxns, hemolytic disease of the newborn, thrombocytopenia
Type 3 Hypersensitivity Rxn
- Immune complex
- Antigen-Antibody complexes (IgG, IgM)
- Complement involved
- Macrophages, mast cells
- Cytokines involved
- Immune complex mediated (immune complex disease)
- Immune complex desposition, inflammation
- Arthus rxn, serum sickness, SLE
Type 4 Hypersensitivity Rxn
- T-cell dependent
- No antibody
- No complement involved
- Antigen specific T-cells
- T-cell cytokines involved
- T-cell mediated, delayed type
- Inflammation, cellular infiltration
- Allergy or infection, contact dermatitis
SLE form Discoid (Cutaneous)
Limited to the skin & is identified by the appearance of a characteristic butterfly rash across the nose, neck, & scalp
SLE form Drug-Induced
Occurs after the use of certain prescribed drugs
SLE form Mixed Connective Tissue
Affects 10% of Lupus cases, symptoms & signs of more than one connective tissue disease
Systemic Lupus
More severe than discoid, affects shin, joints, and most any organ/system in the body, including lungs, kidneys, heart, or brain
Neonatal Lupus
Rare condition acquired from the passage of maternal antibodies that can affect the skin, heart, and blood of the fetus
SLE Etiology
Unknown, primary defect in the regulation of the immune system, genetic predisposition, hormones & environmental factors by trigger disease (antibiotics, UV light, stress, drugs *synergistic)
SLE S&Ss
Acute & chronic inflammation, mimic other less serious illnesses, cutaneous, renal, lymphadenopathy, serositis, cardiopulmonary, GI, musculoskeletal, neuropsychiatric, pregnancy
SLE Manifestations
Production of multiple autoantibodies: Antibody-forming B lymphs are stimulated in a relatively nonspecific fashion
Hallmark of SLE?
Circulating Immune Complexes- multiple serum antibodies that react with native or altered self-antigens
Diagnostic evaluation of SLE?
Histologic changes, hematologic, & serologic abnormalities
SLE antibodies
Nonspecific elevation of IgS-IgM & IgG
SLE Antinuclear Antibodies (ANAs)
IgM, IgG, & IgA
Antibodies to: DNA, histones, nonhistones proteins, nuclear antigens
Lab Evaluation of ANAs
Indirect Immunoflourescent Technique of ANAs
Immunology
The study of the molecules, cells, organs, & systems responsible for the recognition & disposal of foreign (non self material)
Function of the Immune System
To recognize self from non self & to defend the body against non self
Innate Immune System
Ancient form of host defense, germline- encoded receptors, specificity of each receptor is genetically predetermined (natural immune system)
Adaptive Immunity
Augmentation of body defense mechanisms in response to specific stimulus, which can cause the elimination of organisms & recovery from disease, response frequently leaves the host w/ a specific memory (acquired resistance), which enables the body to respond effectively if reinfection w/ the same organism occurs, adaptive immunity is organized around T & B lymphocytes: adaptive immune response
Artificial Passive Immunity
Infusion of serum/plasma
Artificial Active Immunity
Vaccinations
Specificity
Ability of a particular antibody to combine w/one antigen
Memory
Immunologic response to an antigenic stimulus that usually leaves the immune system changed
Mobility
Ability of specific (T&B cells) & non-specific (macrophages, neutrophils) cells of the immune system to circulate
Replicability
Ability of specific & non specific cells of the immune system to produce daughter cells (memory cells)
Non self substances
microorganisms, allergens, & lifesaving organ transplants
Desirable consequences of immunity
natural resistance, recovery, & acquired resistance
