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Flashcards in Adaptive immunity Deck (19)
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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


Bone marrow

Blood, phlegm, black bile, yellow bile

B- cells, lymphocyte

works against free circulating antigen except intracellular antigens (viruses and microbes)





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



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



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



Globular protein - soluble proteins, spherical to elliptical structure






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




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



Aggregates of 2-5 monomers





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


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


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.