Adaptive immunity Flashcards
Adaptive vs Innate
Innate: Defense against any pathogen
Adaptive: Induced resistance to specific pathogen
Louis Pasteur
First to observe immunity in chickens
Injected weakened pathogen which did not cause disease
(weakened by lack of nutrients to multiply)
Emil von Behring
Diphtheria & Tetanus bacteria
Small amounts of toxin in rabbits survived and blood created Antitoxin
Paul Ehrlich
Special property in blood produced by antibodies
Serum factors - factors produced by exposure to bacteria and pathogens
Stem cell line
develops in bone marrow or fetal liver
Stem cell
_Red bone marrow _ Thymus
B-cells T-cells
both migrates to lymphoid tissue
(Spleen, Lymph nodes)
Humoral immunity vs Cellular immunity
Humoral
Bone marrow
Blood, phlegm, black bile, yellow bile
B- cells, lymphocyte
works against free circulating antigen except intracellular antigens (viruses and microbes)
Cellular
Thymus
T-cells, lymphocyte
Needed to combat intracellular pathogens & Cancer
T-Cells responds to antigen via TCR (t cell receptor)
T Cells need APC (Antigen presenting cells) via MCH
Antigen vs Antibodies
Immune system reponse
Antigen
Highly specific immune response
Are proteins or large polysaccharide
(Capsules, cell wall, flagella, toxin, fimbriae, viral coat)
Non microbe component
Pollen, egg whiate, blood cell surface, serum proteins, surface molecules of transplanted tissue/organs
Epitopes
This is how antibodies recognizes antigens
An antigen can have many epitopes
(Size, shape, chemical structure)
Hapten + carrier moleculs
=Hapten-carrier conjugate
Penicillin + host proteins = is an antigen, produces allergic response
Antibodies
Globular protein - soluble proteins, spherical to elliptical structure
Ig
Antibody monomers
Composed of 4 proteins
2 heavy chain
2 light chain
Each Antibody has 2 identical binding site that binds to eptiopes (antigen binding site)
Variable vs Constant region
Stem of antibody is Fc region
Ig
Has different immune reponse roles
IgG - Monomer, 80% of serum, Fixed complement, blood, lymph and intestine, crosses placenta, enhances phaogcytosis, neutralizes toxins/virus, protects fetus, 23 days half life
IgM - Pentamer, 5-10% serum, Fixed complement, blood lymph, b cells, Agglutinates microbes, 5 days half life, first antibody produced
IgA - Dimer, 10-15% of serum, Mucosal protection, secretion, 6 days half life
IgD - monomer, .2% of serum, blood, lymph, b cells, initiate immune response, 3 day half life
IgE - Monomer, .002% of serum, mast cell, basophils, blood, allergic reaction, lysis of parasitic worms, 2 day half life
Multimers
Aggregates of 2-5 monomers
B-cells
Produces antibodies when activated.
Need assistance from TH (T dependaent antigen)
MHC - Major histocompatibility complex - b cells fragments combine with MHC aka antigen processing & presentation
Clonal expansion - B cells divide & daughter cells are produced which synthesize and secretes antibodies
Carries Ig on cell surface
2 types of daughter cell
Plasma cell - Antibodies
Memory Cell - Long lived and responsible for secondary reponse
T-independent antigens
B cells w/o T cell stimulation
Binds to multiple receptors
Repeating subunits
Protective mechanism of binding antibodies to antigens
Agglutination
Opsonization (antigen is coated to enhance ingestion by phagocytes)
Activation of complement (causes inflammation & lysis)
Neutralization (Blocks Adhesion & Neutralize toxins)
Cytotoxicity (Antibody attaches to target cell causing macrophage, eosinophil, NK cell destruction)
T Cells
glycoproteins
T helper cells (CD4+)
helps humoral immunity
MHC Class II binds to B cells and APC
Effector cells
- TH1 - produces IFN
- TH2 - activates eosinophils/B cells to proudce IgE
- Memory cells
T cytotoxic cells (CD8+)
becomes cytotoxic t lymphoctye (CTL)
Binds to MHC class I
Recognizes & destroys infected cells/cancer
Are Endogenous antigens
CTL releases perforin and granzymes (induce apoptosis)
T regulatory cell suppress t cells against self
Adaptive Immunity
Naturally acquired active immunity - resulting from infection
Naturally acquired passive immunity - Transplacental or colostrum
Artifically acquired active immunity - Injection of antigen (vaccination)
Artifically acquired passive immunity - injection of antibody
Vaccine types
Attenuated whole agent vaccines - use of live weakened microbes. Provides live long immunity w/o booster
(MMR, measles, mumps, rubella, polio)
It can revert to pathoglogical form
Inactivated whole agent vaccine - uses killed microbes
(cholera, Pneumococcal pneumonia)
Toxoids - inactivated toxins
(Tetanus, diptheria)
Subunit - fragments of microbe that stimulate an immune response. Has fewer adverse effects cuz they cannot reproduce
Conjugated - based on capsular polysaccharides
Nucleic Acid - DNA is injected in muscle producing protein encoded antigen. Stimulates humoral and cellular immunity
Adjuvants - use chemical additive when vaccines fail to stimulate immune response.
