antibodies
DESCRIPTION
Presentation made by using Interactive Physiology 10 and some books, some pictures from Ryan Medical MicrobiologyTRANSCRIPT
A N AT O L I Y T I M O F E E V
N OV I S A D 2 0 1 2
ANTIBODIES
WHAT DID YOU EXPECT?
TERMINS IN USE
• ANTIGEN – three-dimensional protein molecule on the surface of pathogen• PATHOGEN – disease causing agent• ANTIBODY – protein molecule, that is produced by
immune system
ANTIBODIE ARE
Globuline proteins
Immunoglobulines
Gamma – globulines ( )𝞬
IMMUNOGLOBULINE STRUCTURE
IMMUNOGLOBULINES ARE GLUCTOPROTEINS
Made up ofL (light)H (heavy) chains
Weight because of molecular massL = ± 25000H = 50000 ± 70000IgG=2H+2L chains
LIKE A LEGO! IS NOT IT?
2 HEAVY
2 HEAVY+ 2 LIGHT
!!!!+DISULFIDE BOND!!!!
L AND H PARTS HAVE VARIABLE AND CONSTANT CHAINS
FAB- AND FC- FRAGMENTS
CommentFab sites bind antigen(fragment antigen bidning)Fc fragment recognized by complement, phagocytes (fragment constant)
ANTIBODY MOLECULE IS SYMMETRICAL
•Both heavy chairs are identical•Both light chairs are identical
Would quickly fall apart because it is only loosly connected by disulfide bonds.
CAN BE
•Bound to B cells as receptor
•Secreted into plasma, like “freelancers”
IMMUNOGLOBULINE CLASSES
IgG
IgM
IgEIgD
IgA
MNEMONIC RULE
TOTAL AMOUNT OF IMMUNOGLOBULIN
IgG75.602%
IgA15.120%
IgM9.072%
IgD0.202%
IgE0.004%
In serum
IgG H2L2(FORMLE)
•IgG1 – 65%IgG2IgG3IgG4/according to H chain and S-bond location
CHARACTERISTIC OF IgG
• Most abundant• Predominant in secondary response• Can cross the placenta• Opsonizes (enhance phagocytosis)• Transfer
IgA 2*(H2L2)+J+s.c.
J – means Joining chair, what is needed for connecting of 2 Fc – fragments+ secretory component
MAIN IMMUNOGLOBULIN IN SECRETIONS IgA
•Saliva•Tears•Respiratory•Intestinal•Genital
IgA
Secretory component is a polypeptide synthesized by epithelial cells that provide for IgA passage to the mucosal Surface>
Prevent attachment
IgM 5*H2L2+J
• Earlier produced in primary response• Pentamer• Agglutination(most efficient)• Highest avidity• First component of compliment
10 BINDING SITES
HAS NO KNOWN A.B. FUNCTION
IgE
• Medicates immediate hypersensitivity > anaphylactic reaction• Defense against parasites• Does not fix compliment
Property IgG IgA IgM IgD IgE
Serum[mg/dL]
1000
200 120 3 0,05
Sedimention coefficient 7S 7S/11S 19S 7S 8S
MW(*1000) 150 170-400 900 180 190
Struture -mer Mono- Mono-/di- Mono-/penta-
Mono- Mono-
H chain symbol γ α μ δ ΕCompliment ficsation + - + - -Transplacental passage + - - ? -Mediation of allergic reaction
- - - - +
Found in secretions - + - - -Opsonization + - - - -Antigen receptors of B cells
- - + ? -
Polemeric form contain J-chains
- + + - -
ISOTYPES
• Greek: Isos – equal
”We are different, but we are same”
Amino acidic differences in constant regions of antibodies, according to it we have:IgG(1-4)/IgA(1-2)/IgM/IgD/IgEAll people have it, but each of antigen has own specific structure and functions, same for all humans.
ALLOTYPE
• Greek: Allos – other
“ We are same, but we are different “
Antigenic features of antibodies that vary among individuals. Different alleles = different L and H chains.
𝞬 H chain contein an allotype called Gm(gamma) which can differ to one- or two-amino-acids.k L chains are called Inv(individual, patients name)
IDIOTYPES
• Greek: Idios – own
“We are same, but our difference inside of us”
Antigenic determinants formed by the specific amino acids in the hyper variable regions.+ Secondary response against cross-reacting agents-Autoimmune diseasesallergy, anaphylaxis, asthma, transfusion reactions, rheumatoid arthritis, and type I diabetes.
HUMORAL IMMUNITY
Humoral means antibody- mediated immunity. Directed against:• Toxin-induced diseases• Infections (virulence due to polysaccharide capsule)• Certain viral infections
• Systemic• Involves B and T lymphocytes• Specific• Has memory
CLASSIFICATION
THE PRIMARY RESPONSE
• First contact with antigen• Long lag period (7-10 days)• First antibodies are IgM 7 day• Constant increase of antibody concentration• Followed antibodies IgG/IgA production• Elimination of alien• Decrease of antibody concentration (35 day)• !Keeping of some memory cells!
THE SECONDARY RESPONSE
• Contact of B- memory cells with same or cross-reacting alient• Rapid antibody response( lag period 3-5 days)• Totally higher increase of antibodies amount• Longer period of decreasing of antibodies concentration (of IgG)
DIFFERENCES IN CONCENTATION
MULTIPLE ANTIGENS
• When two or ore antigens are presented at the same time, organism produces antibodies to each of them.
Therefor it is possible to use complex vaccines and immunization got possible.
• DPT(diphtheria, pertussis, tetanus)• MMR(measles, mumps, rubella)
FUNCTION OF ANTIBODIES
•Protection against inflectional Agents •Protection against agent products•Neutralization of toxins•Neutralization of viruses•Opsonize microorganisms*
*making of foreign cell more susceptible(available) for phagocytosis
FUNCTIONS (MNEMONIC RULE)
THANK YOU FOR ATTENTION
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