Human antibody diversity?

vetimmunol at vetimmunol at
Wed Mar 13 06:07:18 EST 2002


There are two theories of antibody diversity generation:
1. Germline theory which, states that genes coding for Igs are present 
in germ cell line i.e. egg and sperm.
2. Somatic theory which, states that diversity is generated later by 
some sort of somatic genetic change of few germ line variable (V)genes 
during the differentiation of B cell precursors to mature cells.

The mechanisms proposed by both the theories contibute towards the 
generation of the antibody diversity.

Four mechanisms which adds to the diversity are:
1. Multiplicity of the V,D and J germline gene segments.
2. The freedom at which these segments combine and form chains.
 Further diversity is added by:
3. Generating different nucleotides sequences at the junction of V, D 
and J genes segment i.e.junctional diversity by imprecise or flexible 
And the 4th one is through Somatic hypermutation.

Together all these mechanisms are capable of producing aprrox. 
1000,000,000 immunoglobulin molecules.

You can read details in :

Tonegawa 1983 Nature 302: 575
Ledder 1982 Sci.Am. 246:102
Golub 1987 Cell 48: 723

Good Luck!

Devender Kr. Saini,
Research associate,
College of Veterinary Science,
CCS Haryana Agricultural University,Hisar,Haryana,

----- Original Message -----
From: BL <lo1 at>
Date: Monday, March 11, 2002 9:10 pm
Subject: Human antibody diversity?

> Does anyone know what the diversity of antibodies produced by the 
> humanimmune system is? I have come across several numbers and 
> wonder where I can
> obtain a definitive answer (from 10e10 to 10e30!!). Thanks for any 
> info.


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