This document summarizes ABO blood grouping and the Rh factor. It discusses how Karl Landsteiner discovered the ABO blood group system in 1900. It describes antigens and antibodies related to ABO blood types and the Rh factor. Specifically, it explains that ABO antibodies are IgM antibodies that cannot cross the placenta, while Rh antibodies are IgG antibodies that can. The document also outlines the antigen-antibody reaction process and notes how optimal concentrations are required for agglutination.

1. ANTIGEN-ANTIBODY REACTION
ABO BLOOD GROUP AND RH- FACTOR
SHARDA UNIVERSITY
SCHOOL OF MEDICAL SCIENCE AND RESEARCH
DERPARTMENT OF PHYSIOLOGY
Sanjog Bam
HUMAN BIOLOGIST
MSc .Physiology

2. LEARNING OBJECTIVES
• ABO Blood group system
• Antigen , Antibody and alleles
• Rh- factors
• Ag-Ab reaction
• ABO incompatibilty and Rh-compatibility

3. ABO BLOOD GROUP
• Austrian scientist Karl Landsteiner identified the ABO
blood group (1900).
• LANDSTEINER's LAW-
1.If an agglutinogen is present on red blood cell membrane
,the corresponding agglutinin must be absent in the
plasma.
2.If an agglutinogen is absent on red blood cell membrane,
then corresponding agglutinin must be present in the
plasma.
• Blood groups are inherited from both parents.
• The ABO blood type is controlled by a single ABO gene
with three types of alleles : i, IA, and IB.

4. ANTIGENS AND ANTIBODY
ABO antibodies are cold antibodies, IgM type :cannot cross placenta
Rh antibodies are warm antibodies , IgG type: can cross placenta

5. Located in Chr9, homologous chromosomes include both parental and maternal
Example of triallelism
Six genotype
Four phenotype

7. Rhesus
monkey
rabbit
Human
85%- agglutinate-D antigen-
Rh+ve
15%-no agglutination-no D
antigen –Rh-ve
Blood transfer
Transfer antibodies
Something common among human and monkey’s RBC
Rh-factor
Rh-antigens
Transmembrane proteins
D-antigens

8. Stages of Ag-Ab interaction
• Primary interaction
o No visible effect with naked eyes
o Force of interaction: electostatic force, hydrogen
bond , Vander wall’s bonds
• Secondary interaction
o Demonstrable events such as precipitation ,
agglutination
o Alternatively activation of serum complement
With IgM ,better agglutination takes place than IgG antibodies
With IgM- large macroscopic aggregates
With IgG- smaller aggregates .
Ag and Ab should be in optimal conc. for aggulutination

10. THANK YOU