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[Abnormality of CD4 molecule--OKT4 epitope deficiency]
T Takenaka1, K Kuribayashi, M Tsukiyama
1Department of Laboratory Medicine, Wakayama Medical School.
Rinsho Byori. the Japanese Journal of Clinical Pathology
|January 1, 1995
Summary
OKT4 epitope deficiency, a trait affecting T-lymphocytes, is linked to a specific CD4 gene mutation. This autosomal codominant condition does not impact HIV susceptibility or immune responses.
Area of Science:
- Immunology
- Genetics
- Molecular Biology
Background:
- OKT4 epitope deficiency affects T-lymphocyte surface markers.
- This deficiency presents in both heterozygote and homozygote forms.
- Understanding the genetic basis and implications of this deficiency is crucial.
Purpose of the Study:
- To identify the genetic cause of OKT4 epitope deficiency.
- To determine the incidence of this deficiency in the Japanese population.
- To investigate the functional consequences of OKT4 epitope deficiency.
Main Methods:
- Population screening of 1,478 Japanese individuals.
- Hardy-Weinberg equilibrium calculation for heterozygote estimation.
- DNA sequencing of CD4 cDNA in affected families.
- Transfection of mouse L cells with mutant CD4 cDNA.
Main Results:
- OKT4 epitope deficiency is an autosomal codominant trait.
- A single nucleotide substitution (CGG to TGG) in the CD4 gene causes the deficiency.
- The mutation leads to an arginine to tryptophan substitution, altering CD4 hydrophobicity and conformation.
- No abnormalities were observed in HIV susceptibility, CD4 internalization, IL-2 production, or IL-2 receptor expression.
Conclusions:
- The identified CD4 gene mutation is responsible for OKT4 epitope deficiency.
- The deficiency does not appear to impair key T-lymphocyte functions or HIV resistance.
- Further research may explore potential subtle impacts or related immune phenomena.