I-J expression is not associated with murine chromosome 4

Area of Science:

• Immunogenetics
• Molecular immunology
• Major histocompatibility complex research

Background:

• The I-J determinant was initially mapped to the murine major histocompatibility complex (H-2) region.
• Cloning efforts of the H-2 complex failed to identify DNA sequences corresponding to I-J.
• Alternative hypotheses proposed a locus on chromosome 4 for I-J expression.

Purpose of the Study:

• To investigate the expression of I-Jk molecules in AKR/J and A/WySn mouse strains.
• To determine the functional capacity of I-Jk-bearing suppressor factors in these strains.
• To re-evaluate the chromosomal mapping of I-J-determining genes.

Main Methods:

• Analysis of I-Jk surface molecule expression on AKR/J spleen cells.
• Assessment of functional suppressor factors produced by AKR/J and A/WySn mice in response to poly(Glu50Tyr50).

Main Results:

• AKR/J spleen cells were confirmed to express I-Jk surface molecules.
• Both AKR/J and A/WySn mouse strains demonstrated the production of functional I-Jk-bearing suppressor factors.
• These findings contradict the hypothesis that these strains are I-Jk negative.

Conclusions:

• The expression of I-Jk molecules in AKR/J and A/WySn mice challenges previous mapping data.
• The production of functional I-Jk-bearing suppressor factors supports the presence of I-Jk determinants in these strains.
• Current data suggest that the proposed mapping of I-J-determining genes to chromosome 4 may require further revision.