T lymphocytes in infectious mononucleosis. I. T cell death in vitro.

A large proportion of T lymphocytes isolated from the peripheral blood of acute infectious mononucleosis (IM) patients rapidly die when cultured in vitro, with greater than 50% dying within 12-15 h of seeding and up to 80% dying within 24 h. The cells die by apoptosis, a morphologically distinct mode of cell death that occurs in circumstances where death is a regulated event such as in embryonic development and hormone-dependent atrophy. In contrast, the level of cell death remained low in cultures of lymphocytes from controls and in the T cell depleted subpopulation from acute IM patients, with less than 2% and 10% of the lymphocytes dying by apoptosis after 36 h in culture, respectively. The rapid death of acute IM T cells in vitro does not involve soluble factors (including the serum fraction) or T cell to T cell contact. It is suggested that this observation may necessitate a re-evaluation of IM T cell function in vitro.     

T helper cells.

B-cell proliferation and differentiation is controlled by T helper cells. Recent studies have determined that the expression of a novel, 39 kD, T-cell membrane protein is responsible for inducing T-cell-dependent B-cell activation. The receptor for this protein on the resting B cell is CD40. Once activated, B cells are induced to grow and differentiate by the elaboration of interleukin-4 and interleukin-5 from activated T cells. Together, T cell-B cell contact and soluble factors provide all the signals required for B-cell growth and differentiation.     

Alloreactive cytotoxic T cells. I. Alloreactive and allorestricted cytotoxic T cells

Nylon wool-nonadherent spleen cells from three inbred mouse strains of H-2k (CBA), H-2d (BALB/c) and H-2b (C57BL/6) haplotype were co-cultured with 2,4,6-trinitrophenyl (TNP)-modified or nonmodified allogeneic stimulator cells in a limiting dilution system. Using a recently described restimulation protocol, a surprisingly large number of splenic cytotoxic lymphocyte precursors (CLP) was clonally expanded in this primary in vitro response to allo-H-2 plus TNP determinants; measured CLP frequencies ranged from 1/30 to 1/300. The lytic specificity patterns of individual microcultures (selected for a high probability of clonality) were defined by split well analysis, and were furthermore followed up in time by sequentially reassaying microcultures at different time points of in vitro incubation. This analysis revealed the following: a large fraction of cytotoxic T lymphocyte clones lysed TNP-modified but not nonmodified allogeneic concanavalin A blast targets, i.e., were allorestricted; this was found in all 6 allogeneic strain combinations set up with b, k and d haplotype mice; allorestricted lytic patterns predominated in microcultures with low numbers of responder cells per well, and at late time points of in vitro culture; allorestricted lytic cultures were specific for the stimulating allogeneic H-2 plus TNP determinant(s); and allorestricted lytic patterns were also found in microcultures stimulated by nonmodified allogeneic cells. To our knowledge, these are the highest CLP frequencies yet reported in limiting dilution systems that used a specific (re)stimulation protocol and measured the lytic responses obtained in a specificity-controlled readout.     

Subpopulations of human T lymphocytes. XIII. T cell subpopulations (T mu and T gamma) in children with bronchial asthma

Peripheral blood from children with bronchial asthma was examined for the proportions of T cells, T cells with receptors for IgM (T mu) or IgG (T gamma), and locomotion of T cells in the presence of chemoattractants casein and endotoxin-activated serum (EAS). Patients were divided into two groups: (A) children with asthma who were not taking any medication for at least 3--5 days prior to the study and (B) children who were taking aminophylline when this study was carried out. Proportions of T cells and T gamma cells in patients from both groups were comparable to age and sex matched controls. T mu cells in group A patients were comparable to those of the control group, but group B patients had significantly lower proportions of T mu cells when compared with those of controls and of patients in group A. Locomotion of T cells in the presence of casein and EAS was comparable in all three groups. The significance of these findings is discussed.     

Immuno-proteomic analysis of Trichinella spiralis,T. pseudospiralis,and T. papuae extracts recognized by human T. spiralis-infected sera

Parasitology Research - The present study explored potentially immunogenic proteins of the encapsulated (Trichinella spiralis) and non-encapsulated (T. pseudospiralis, T. papuae) species within the...