The nucleotide sequence of two new DP alleles, DPA1*02015 and DPB1*8401, identified in a Chinese subject

The HLA-DP genes (HLA-DPA1 and -DPB1) are encoded by the major histocompatibility complex (MHC) on human chromosome 6. They are involved in the presentation of antigen to CD4+ T cells as part of the class II antigen-presentation pathway. During a small study of Oriental subjects (11 Chinese and 26 Japanese subjects), one Chinese subject was identified as having numerous heterozygous sites within the second exon of both DPA1 and DPB1. These were further analysed using novel codon-specific primers. Sequencing analysis using these primers determined the subject to have DPA1*0103/*02015 and DPB1*0501/*8401; these new alleles have been submitted to GenBank and assigned the accession numbers AF098794 and AF077015, respectively.     

PD-1-Expressing SARS-CoV-2-Specific CD8+ T Cells Are Not Exhausted,but Functional in Patients with COVID-19

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Are primed CD4+ T lymphocytes different from unprimed cells?

Primed and unprimed lymphocytes are usually classified as separate subsets of cells, based on phenotypic and functional distinctions. In the case of CD4⁺ T lymphocytes, primed cells are thought to proliferate more vigorously, quickly and easily, and to release a different profile of cytokines, than their naive equivalent. However, most of these data were obtained from studies in which populations of lymphocytes were compared before and after antigenic stimulation, and therefore did not distinguish between the effects resulting from the clonal expansion of specific precursor cells within such populations and those due to cell differentiation per se. We have investigated the contribution of precursor cell frequency to some of the functional changes observed in populations of CD4⁺ T cells following antigenic stimulation, using approaches in which antigen-specific precursor frequencies are high in both primary and secondary stimulations: mixed leukocyte reaction responses and cells from αβ T cell receptor transgenic mice. Our data suggest that when equivalent numbers of antigen-specific naive and previously primed CD4⁺ responder T cells are compared, there is no difference in their potency to proliferate but only the previously activated subset can generate cytokines such as interferon-γ.     

Vasculogenesis and angiogenesis in the subcardinal venous plexus of quail mesonephros: spatial and temporal morphological analysis

Vasculogenesis and angiogenesis are involved in a coordinated program for the development of the mesonephric subcardinal venous plexus of quail embryo. Vasculogenesis occurs between days 3 and 4 of incubation, while angiogenesis takes place from day 5 to day 7. Examination of vascular corrosion casts and whole mounts, and tissue sections labelled with specific markers to hemangioblast lineage (QH1, LEP100 and AcPase activity), allowed us to distinguish six phases in the formation of subcardinal plexus. (1) Appearance of isolated angioblast-like cells where the subcardinal plexus will form. (2) Alignment of angioblast-like cells into cellular strands. (3) Formation of compact vascular cords by association of angioblast-like strands. (4) Polygonal interconnection of vascular cords to constitute the primary subcardinal plexus. In this stage, isolated angioblast-like cells were present inside inter-vascular spaces. (5) The splitting of primary inter-vascular spaces by angiogenic sprouts to form secondary subcardinal plexus (outward angiogenesis). Isolated angioblast-like cells were not present in this stage. (6) Expansion of the secondary subcardinal plexus by insertion of slender transcapillary tissue pillars (inward angiogenesis) and angiogenic sprouts. We also describe three morphogenetic gradients during the development of the subcardinal plexus: ventral-to-dorsal, cranial-to-caudal and lateral-to-medial. Accepted: 9 November 2001     

Tryptase and histamine release during aspirin-induced respiratory reactions

The involvement of mast cells in the pathogenesis of aspirin (ASA)-induced respiratory reactions was investigated by measuring serum levels of tryptase, a neutral protease that is a specific marker of mast cell activation. ASA challenges were performed in 17 ASA-sensitive patients with asthma and rhinosinusitis, and tryptase and histamine levels were measured in their venous blood samples. In three subjects who experienced moderate to severe respiratory reactions extending to the skin and/or gastrointestinal tract, marked elevations of tryptase levels in postreaction serum samples (peak levels, 51.9 and 40.0 ng/ml) were discovered in two of these three subjects, and a small elevation of tryptase occurred in the serum of the third subject (3.1 ng/ml peak). Plasma histamine levels in postreaction samples were significantly elevated over baseline values in all three subjects (delta mean plasma histamine, 238 pg/ml versus 56 pg/ml for the remaining 14 subjects; p less than 0.04). In the remaining 14 subjects, who experienced similar respiratory reactions without extrapulmonary symptoms during aspirin challenge, changes in tryptase and histamine levels were not observed.     

Effect of interleukin 1 on adrenal function in mice

Laboratory of Regulation of Immunopoiesis, Institute of Clinical Immunology, Siberian Branch, Academy of Medical Sciences of the USSR, Novosibirsk. (Presented by Academician of the Academy of Medical Sciences of the USSR V. P. Kaznacheev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 105, No. 3, pp. 311–313, March, 1988.     

Polyamines in Trichomonas vaginalis

Trichomonas vaginalis was grown in a modified Bushby's medium and putrescine, spermidine and spermine levels were determined in extracts from 24- and 48-h cultures and also in the culture media. All three polyamines were present in T. vaginalis extracts; the putrescine level and putrescine/spermidine ratio were much higher than those reported for other protozoa or for mammalian tissues. There were no significant differences between 24-h and 48-h amine levels per mg protein in these extracts, but amine levels per cell were higher at 24 than at 48 h. The spent culture media had a much higher putrescine content than corresponding uninoculated media and it was concluded that T. vaginalis secreted putrescine into the culture medium.     

Adjunct effect of loratadine in the treatment of acute sinusitis in patients with allergic rhinitis

H₁-blockers are often added to the standard treatment of acute sinusitis, but this is not supported by a controlled study. A multicentric, randomized, double-blind, placebo-controlled, parallel-group study was done in 139 allergic patients (15–65 years) to assess the adjunct efficacy of loratadine in acute exacerbation of rhinosinusitis. Sinusitis was diagnosed by symptoms and confirmed by rhinoscopy and sinus radiograph. Allergy was characterized by skin tests, RAST, and history. Patients were treated with antibiotics (14 days), oral corticosteroids (10 days), and loratadine (10 mg OD) or placebo (28 days). Treatment efficacy was assessed over 28 days by symptom scores quoted daily by patients. Physicians also rated total symptom scores at entry and at day 28. At entry, both groups had similar symptoms. Placebo-treated patients improved significantly, but patients who received loratadine had a significantly greater improvement in sneezing ( P =0.003) after 14 days, and in nasal obstruction ( P =0.002) after 28 days. Physicians found that patients receiving loratadine were significantly improved compared to placebo patients ( P =0. 0125). Loratadine in addition to standard therapy was found to improve the control of some symptoms of sinusitis.     

Lack of intermediate-affinity interleukin-2 receptor in mice leads to dependence on interleukin-2 receptor α, β and γ chain expression for T cell growth

An interleukin (IL)-4 dependant mouse T cell clone 8.2 derived from an IL-2-dependent T cell line was characterized. As measured by flow cytometric analysis and Northern blotting, it expresses IL-2 receptor β (IL-2Rβ) and γ (IL-2Rγ) chains, but has lost expression of IL-2 receptor α chain (IL-2Rα). To investigate the properties of the mouse IL-2Rβγ complex and the role of IL-2Rα gene expression, this clone was further studied. T cell clone 8.2 has lost the capacity to bind ¹²⁵I-labeled human IL-2 under experimental conditions able to detect intermediate-affinity IL-2R in human cells. Mouse IL-2 is unable to block the binding of mAb TMβ1 to 8.2 cells. Under the same experimental conditions, mouse IL-2 blocks the binding of TMβ1 to C30-1 cells expressing the IL-2αβγ complex. Since TMβ1 recognizes an epitope related to the IL-2 binding site of IL-2Rβ, these results can be taken as a demonstration that mouse IL-2Rβγ does not bind mouse IL-2. Furthermore, T cell clone 8.2 does not proliferate in response to recombinant mouse or human IL-2. On the other hand, T cell transfectant lines expressing heterospecific receptors made of the human IL-2Rβ and mouse IL-2Rγ chains bind ¹²⁵I-labeled human IL-2 and proliferate in response to IL-2. This establishes the difference between mouse and human IL-2Rβ chains. Transfection of T cell clone 8.2 with human IL-2Rα genes restores their capacity to proliferate in response to IL-2. In addition, all transfectants grown in IL-2 express the endogeneous mouse IL-2Rα chain. When grown in IL-4, the endogeneous mouse IL-2Rα gene remains silent in all these transfectants. These results show that, contrary to the human, the mouse does not express an intermediate-affinity IL-2R. Expression of the IL-2Rα gene is therefore required for the formation of the functional IL-2R in mice.