Shinhachiro Tomino

Age-related decrease in frequencies of B-cell precursors and specific helper T cells involved in the IgG anti-tetanus toxoid antibody production in humans

Abstract B cells from each of 12 aged subjects (72 to 83 years old) and 12 young adults (24 to 32 years old) were cocultured with pokeweed mitogen (PWM) and an equal number of T cells isolated from a single tetanus toxoid-boosted donor for 7 days. The quantities of IgG antibody produced were significantly different in the two groups, with geometric means of 142 and 181 ng/ml in young adults, and 14 and 33 ng/ml in aged donors at 2 and 4 weeks after booster immunization, respectively ( P P = 0.02 at 4 weeks). There was no evidence indicating increased specific suppressor activity in the aged. Precursor frequency of B cells active in IgG antibody production was approximately 5.2-fold less in the aged than in young adults ( P = 0.01). Tetanus toxoid-specific helper T-cell frequency also decreased by 3.5-fold in the aged as compared with young adults ( P = 0.05).

T-cell suppression of immunoglobulin synthesis in ataxia telangiectasia: Restriction of suppressor activity to B cells from unrelated donors

Abstract Ataxia telangiectasia is a genetically transmitted disorder, characterized by progressive neurologic dysfunction, superficial telangiectasia, and abnormalities of cellular and humoral immunity. We examined a 13-year-old female with this disorder, whose peripheral T cells were found deficient in their ability to collaborate with B cells from unrelated normal individuals, but not from each of her parents and her sisters upon coculturing in the presence of pokeweed mitogen (PWM). In addition, the patients T cells (Tp) suppressed the Ig production by PWM-stimulated peripheral blood lymphocytes (PBL) from allogeneic normal individuals but not from her parents. In contrast, irradiated T cells from this patient could collaborate to produce Ig with allogeneic B cells. HLA studies revealed that PWM-induced Ig production by PBL from the relatives was not suppressed by Tp irrespective of HLA phenotype of the donor. These data strongly suggest that Tp subpopulation has both a genetically unrestricted helper and a genetically restricted suppressor, a hitherto unreported phenomenon.

Adenosine uptake in pyrimidine 5'-nucleotidase deficient human erythrocytes via a high affinity transport system

Using a pulse-labeling technique,14C-adenosine uptake into pyrimidine 5′-nucleotidase (P5N) deficient erythrocytes (RBC) was found to be impaired. The Lineweaver-Burk plot showed Km values of 2.0×10−3 mM and 0.2 ×10−3 mM for normal RBC and P5N deficient RBC, respectively. These results indicate that P5N is one of regulators of the adenosine transport system and/or is associated with adenosine carrier protein.