Search PubMed⌕ Search

Biomedical subjects

T Tada

Publications and source records attributed to T Tada.

At least 397 records · Page 22Linked to original sources
PubMed1982

Two loci in I-J subregion of the H-2 complex controlling molecules selectively expressed on suppressor and helper T cells.

Different batches of alloantiserum directed at the I-J subregion products of the H-2 major histocompatibility complex (anti-I-J) induced either suppression or augmentation of the in vitro secondary antibody response when added in a minute quantity to the culture of primed spleen cells. The suppressive or augmenting effect of the individual antiserum was found to be determined by its predominant specificity for either one of the two different molecules, both encoded in the I-J subregion, that were selectively expressed on functionally different subsets of T cells, i.e., suppressor (Ts) and helper (Th2) T cells. This was determined by the differential absorption of antiserum with Lyt-1+ and Lyt-2+ T cells as well as with suppressor hybridomas that express an I-Jk product. It was found that the absorption of an anti-I-J antiserum with Lyt-1+ T cells resulted in the loss of activity to eliminate a set of helper T cells (Th2) while leaving the ability to affect antigen-specific suppressor T cells (Ts). The absorption of the same antiserum with either Lyt-2+ T cells or suppressor hybridomas eliminated the activity to kill Ts but not Th2. Thus, the results indicate that the I-J subregion accommodates two or more loci that code for discrete molecules expressed on functionally different subsets of T cells. Because the simple addition of a minute quantity of antisera to the culture resulted in the modulation of antibody response presumably by affecting these two sets of T cells, it is suggested that I-J subregion products act as functional molecules in regulatory cell interactions.

Animals↗
PubMed1981

Effect of Bacillus Calmette-Guérin cell wall skeleton on the induction of the cytotoxic and suppressor T cells against syngeneic tumor in the mouse.

The effect of Bacillus Calmette-Guérin cell wall skeleton (BCG-CWS), which is one of the well-established immunopotentiators, on the induction of either cytotoxic or suppressor T cells against syngeneic tumor S1509a was investigated by an in vitro assay system. BCG-CWS showed an apparent augmenting activity in the induction of cytotoxic T cells against a syngeneic tumor when it was administered subcutaneously into mice with mitomycin C (MMC)-treated tumor cells in a form of oil-in-water emulsion. In addition, cytotoxic T cell activity was dominantly generated in regional lymph nodes. Furthermore, the immunized animals developed stronger resistance against the second inoculum of the same viable tumor cells. However, BCG-CWS had no effect on the induction of suppressor T cells in tumor-bearing host (TBH), and could not induce cytotoxic T cells against the homologous tumor in TBH in which suppressor T cells had been rapidly activated. The growth of tumor was neither suppressor nor enhanced, even if an oil-attached BCG-CWS was administered in TBH.

Animals↗
PubMed1981

Allelic polymorphism of murine IgE controlled by the seventh immunoglobulin heavy chain allotype locus.

Two alloantisera against hybridoma-derived IgE detected allotypic determinants expressed on the murine epsilon chain. An antiserum raised in BALB/c mice against monoclonal IgE of C57BL/6 origin reacted exclusively with IgE of strains having Igh-1b (IgG2 a) allotype. The second antiserum, C57BL/6 anti-BALB/c monoclonal IgE, reacted with IgE of strains having Igh-1a, Igh-1d, Igh-1e and Igh-1j allotypes. The genetic studies of (BALB/c x C57BL/6)F1 and backcross F2 animals indicated that the locus controlling the IgE allotype is linked to the Igh-1 locus. This was further confirmed by the possession of respective IgE allotypes by Igh-C congenic mice, BALB/c and BAB-14, C3H.SW/Hz and CWB/Hz. Thus, the allotype detected on the epsilon chain is controlled by the seventh murine immunoglobulin allotype locus, and should be designated as the Igh-7 allotype.

Alleles↗
PubMed1981

Ia antigens on antigen-presenting cells do not carry the same Ia specificities as detected on suppressor and helper T cells.

The passage of spleen cells through a tightly packed nylon wool column partially separated two populations of cells required for the antigen-induced secondary proliferative response of T cells. The proliferating T cells were in the nylon wool column-passed cell population, but the addition of a small number of nylon-wool-adherent cells was required for their maximal proliferative response. Such adherent cells were non-T, non-B, Ia antigen-positive cells serving as antigen-presenting cells. Ia determinants on this cell type are encoded in two separate I subregions, I-A and I-E/C, and they are expressed simultaneously on the same cells. Antisera specific for I-J subregion gene products having as a known activity the killing of antigen-specific suppressor and helper T cells were unable to kill antigen-presenting adherent cells. The results indicated that at least I-J subregion gene products expressed on suppressor and helper T cells are not present on antigen-presenting accessory cells. The Ia specificities detected on accessory cells follow the cross-reactive pattern found in Ia molecules of B cells, and thus antigen-presenting cells carry Ia antigen identical to those of B cells, and not those of T cells.

Animals↗
PubMed1981

Suppression of IgE antibody response by the fatty acid-modified antigen.

Ovalbumin (OA) of hens was chemically coupled with fatty acids (lauric acid, myristic acid, palmitic acid and stearic acid). These hydrophobically modified antigens were unable to react with mouse antiserum against native OA and were incapable of eliciting primary and secondary anti-OA antibody responses in BALB/c mice. Preadministration of these modified antigens, especially of palmitoyl OA (OA-pal), suppressed both primary and secondary anti-OA IgE antibody responses without affecting IgG antibody production. Administration of OA-pal after the primary immunization resulted in a rapid decrease of the ongoing anti-OA IgE antibody production and inhibited the anamnestic anti-OA IgE antibody response upon subsequent immunization with OA. The passive transfer of spleen cells from OA-pal-treated animals with OA-primed spleen cells suppressed the adoptive secondary anti-OA IgE antibody response in irradiated recipients. The suppressive effect was abrogated by treatment with an anti-T-cell antiserum indicating that suppressor T cells were primed by administration of hydrophobically modified antigens.

Animals↗
PubMed1981

Transposition response in different hypertensive rats.

It was tested whether the transposition response, cardiovascular response complex to change of habitat in the rat, is also an isopressor (without arterial pressure change) response, as it is in normal rats, in different experimental hypertensive rats. It was found to be a pressor response, i.e., arterial pressure was considerably elevated on transposition, in spontaneously hypertensive rats, DOCA salt hypertensive rats and neurogenic hypertensive rats. In renovascular hypertensive rats alone, the response was isopressor.

Adaptation, Physiological↗
PubMed1981

Unique T cell Ia antigen expressed on a hybrid cell line producing antigen-specific augmenting T cell factor.

Hybrid cell lines were established by fusion between keyhole limpet hemocyanin(KLH) binding T cells of A/J mice and an AKR T cell tumor line, BW5147. Hybrids were selected for the presence of Ia antigen and KLH-specific augmenting activity of their extracts in the secondary antibody response. The detailed phenotypic and functional analysis of 1 of these clones, FL10, is reported here. The hybrid was positive for both Thy1.1 and Thy1.2 antigens and possessed the Lyt-1+,2-,3- phenotype. Both VH and Ia determinants were detected on their cell surface. The IA locus was mapped in the I-A subregion, but the Ia specificities were serologically distinct from those of B cell Ia antigen. This was demonstrated by the fact that anti-Ia antiserum preabsorbed with B cells could react with the hybrid cells, whereas none of the monoclonal anti-Ia specific for private and public determinations of Iak could. The extract from the cell line specifically augmented the in vitro secondary antibody response against dinitrophenylated KLH, and this activity was removed by absorption with antigen and conventional anti-Ia antisera. The results indicate that the cell line, FL10, carries Ia antigen unique to the T cell, which is associated with the antigen-specific augmenting molecule.

Absorption↗
PubMed1981

[The effect of the Valsalva and Müller maneuvers on right and left atrial dimensions in man studied by esophageal echocardiography (author's transl)].

The effect of the Valsalva (V) and Müller maneuvers (M) on the right and left atrial dimensions was evaluated by esophageal echocardiography in 8 normal male subjects. During V and M, the right atrial free wall (RAW), interatrial septum (IAS) and left atrial posterior wall were recorded by esophageal echocardiography simultaneously with intraairway pressure (Paw). Right (RAD) and left atrial dimensions (LAD) at atrial end-diastolic were measured at various phases during each maneuver. Mean expiratory effort of +40 mmHg Paw in V and mean inspiratory effort of -40 mmHg Paw in M were maintained for about 10 sec. Both atrial dimensions changed significantly during each maneuver. RAD began to decrease just after the onset of V, while LAD changed little during this phase, after which began to decrease progressively. The leftward displacement of IAS with the simultaneous outward displacement of RAW resulted in an increase of RAD and a decrease of LAD just after the onset of M and the release of V. LAD remained higher than resting value from the second (2--4 sec after the onset) to late phase (just before the release) during M. RAD decreased just after the release of M. Thus, esophageal echocardiography was useful to evaluate both atrial dimensions during V and M.

Adult↗
PubMed1981

[A simple method for enhancing interatrial right-to-left shunt in the diagnosis of small atrial septal defect using contrast echocardiography (author's transl)].

Commonly used contrast echocardiography is often inadequate to detect a small right-to-left (R--L) shunt in minimum atrial septal defect (ASD). We found that the diagnostic accuracy in ASD could be significantly improved by simply employing a Valsalva maneuver immediately followed by a Müller maneuver to enhance the R--L shunt. This procedure enabled contrast echo to be more clearly detected in both the left atrium and left ventricle, compared with conventional contrast echocardiography. The new technique was successful in diagnosing ASD in 5 patients with Qp/Qs ratio less than 2 determined by right heart cardiac catheterization. In conclusion, the diagnosis of a small ASD is greatly improved by simply employing this new procedure of a Valsalva-Müller maneuver during contrast echocardiography.

Adult↗