MCMP 422

Spring 2005

M. Harrison

Study Guide 1

Study Guide to the Structure of Immune Molecules

ProteinSubunitsRegionsDesignationComments

Ig (Ab)light chains (2)V and CVL, CLEach V region contains 3 CDRs and is encoded by V region and J region gene segments. Two C region gene segments:  and 

heavy chains (2)V and CVH, CHEach V region contains 3 CDRs and is encoded by V region, D region, and J region gene segments. Five C region genes: , , , , . Gamma and alpha have subclasses.

BCRIgM(monomeric)V and CAntigen binding unit of the BCR (B cell antigen receptor) contains H and L chains

IgDV and CAntigen binding unit of the BCR (B cell antigen receptor) contains H and L chains

Ig-Signaling subunit of the BCR, invariant (does not varying in amino acid sequence)

Ig-Signaling subunit of the BCR, invariant (does not varying in amino acid sequence)

TCR chainV and CV, CEach V region contains 3 CDRs, together with the  chain makes up the antigen binding subunit of the TCR. V region is encoded by V region and J region gene segments.

 chainV and CV, CEach V region contains 3 CDRs, together with the  chain makes up the antigen binding subunit of the

TCR. V region is encoded by V region, D region and J region gene segments

ProteinSubunitsRegionsDesignationComments

TCR subunit-Signaling subunit of the TCR, invariant (does not varying in amino acid sequence). Component of CD3

 subunit-Signaling subunit of the TCR, invariant (does not varying in amino acid sequence). Component of CD3

 subunit-Signaling subunit of the TCR, invariant (does not varying in amino acid sequence). Component of CD3

 subunit-Exists as a homodimer. Signaling subunit of the TCR, invariant (does not varying in amino acid sequence)

MHC I chaincontains varying1, 2, 3 1 and 2 form peptide binding site. sequences (1 and 2) The invariant 3 region binds

and an invariantCD8

region (3)

2 Micro--Invariant, noncovalently

globulinassociates with  chain

MHC II chainvariable region1Together with  forms peptideinvariant region 2 binding site.

 chainvariable region1Together with 1 forms peptide invariant region 2 binding site

ProteinSubunitsRegionsDesignationComments

CD4---One single invariant protein. Found on the surface of helper T cells, binds the invariant 2 region of MHC II

CD8 chaininvariant-Found on the surface of cytotoxic T cells, binds 3 region of MHC I, combines with  chain to form CD8

 chaininvariant-Found on the surface of cytotoxic T cells, combines with  chain to form CD8