Mechanism of supression of human peripheral blood lymphocytes by platelet activation factor

Institute of Immunology, Ministry of Health of the USSR. Research Institute of Biomedical Technology, Ministry of Health of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR, A. D. Ado.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 108, No. 7, pp. 69–71, July, 1989.     

Reaction of peripheral blood lymphocytes to mitogens from the age aspect

The reaction of peripheral blood lymphocytes from healthy blood donors aged from 19 to 49 years to the mitogens phytohemagglutinin, concanavalin A (con A), and rabbit serum against human thymocytes (ATS) was investigated. A significant decrease in the proliferative response of the lymphocytes to con A was found in subjects over 30 years old. Significant negative correlation was found between the indices of the proliferative response and the age of the donors during stimulation by con A for the whole group of subjects, but for stimulation by ATS only for subjects aged 30–49 years. Analysis of the intensity of incorporation of [³H]-thymidine shows a decrease with age in the proportion of cells with intensively labeled nuclei and an increase in the number of cells with weak labeling of the nucleus both with a decrease in the indices of the proliferative response with age and also when no significant differences were found in these indices.Laboratory of General Pathophysiology, Institute of Psychiatry, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. M. Chernukh.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 11, pp. 600–602, November, 1977.     

A culture system for mitogen-induced proliferation of channel catfish (Ictalurus punctatus) peripheral blood lymphocytes

Summary Techniques are described for the isolation and culture of channel catfish peripheral blood leukocytes in the presence of lymphocyte mitogens. The mitogens used are lipopolysaccharide, concanavalin A, and a mixture of a phorbol ester and the calcium ionophore A23187. Each of these mitogens cause channel catfish lymphocytes to proliferate vigorously in vitro at an optimal culture temperature of 27° C. Essential components of the tissue culture medium employed are 10% human plasma and 5% catfish sera, which act synergistically in supporting the in vitro proliferation of channel catfish lymphocytes.     

Effect of lymphokines on DNA structure in human lymphocytes cultured in vitro: Connection with the cAMP and oligo-A system

Laboratory of Medical Biochemistry, Research Center for the Development and Introduction of Modern Methods of Molecular Diagnosis, Ministry of Health of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences and Academy of Sciences of the USSR R. V. Petrov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 110, No. 10, pp. 417–419, October, 1990.     

Electrophoretic separation of lymphocytes from rat spleen and thymus and their response to mitogens in vitro

Electrophoretic mobility (EPM) of lymphocytes from the thymus and spleen of Wistar and August rats was investigated by free flow electrophoresis and the ability of lymphocytes with different surface electric charges to undergo mitogenic transformation under the influence of phytohemagglutinin and concanavalin A was compared. An in vitro culture showed that splenic lymphocytes can be divided into two principal groups depending on their surface charge: cells with high and low mobility respectively. Separation of the thymocytes showed them to be a group of cells consisting of several (8 to 10) fractions differeing in EPM. Ability of the lymphocytes to be stimulated by mitogens was shown to depend on their surface charge. Stimulation of [³H]thymidine incorporation was observed during exposure of splenic lymphocytes with high mobility in an electric field to mitogens. Lymphocytes with low mobility were not stimulated by mitogens. The subpopulation of thymocytes with low EPM was not stimulated by concanavalin A. Rat thymocytes were shown virtually not to react to phytohemagglutinin irrespective of their EPM.Laboratory for Organ and Tissue Transplantation, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Kovanov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 88, No. 9, pp. 322–324, September, 1979.     

Inhibition of activation of DNA synthesis by immune lymphocytes in mixed normal lymphocyte cultures in vitro

Replacement of normal by immune lymphocytes as reacting cells in one-way mixed lymphocyte cultures (MLC) leads to inhibition of DNA synthesis. this phenomenon is observed regardless of the strain of mice, the method of immunization (in vivo or in vitro), or the method of performing the MLC test (macro-or microcultures, presence of mercaptoethanol in the medium, type of control). Unlike the cytotoxic effect of immune lymphocytes, which follows an acute course with a peak on the eighth day after immunization, inhibition of DNA synthesis in MLC is observed as early as on the second day, it continues for several weeks after immunization, and it can be produced by the addition of a small fraction (5–10%) of immune to normal lymphocytes.Laboratory of Immunochemistry and Diagnosis of Tumors, N. F. Gamaleya Institute of Epidemiology and Microbiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR T. A. Vershilova.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 6, pp. 723–725, June, 1977.     

Effect of hydrocortisone on spontaneous and mitogen-dependent activity of peripheral blood lymphocytes in some vertebrates

The effect of hydrocortisone on functional activity of peripheral blood lymphocytes in different vertebrates during ontogeny was studied by the blast transformation test. Hydrocortisone in a dose of 100 mg/kg inhibited functional activities of T and B lymphocytes in vitro stimulated by mitogens. This inhibitory effect was observed in both young and adult animals. However proliferative activity of concanavalin A-dependent blood T suppressors in rats increased, especially in adult animals (by 3.5 times). Hence, hydrocortisone produced different effects on functional activity of peripheral blood lymphocytes in the studied species, and these effects are dose- and species-dependent.     

DNA structure in peripheral blood lymphocytes from patients with chronic viral liver damages

We studied DNA damages (single-strand breaks and alkali-labile sites) in peripheral blood lymphocytes from patients with chronic viral hepatitis and cirrhosis of mixed etiology. The structure of DNA was estimated fluorometrically by changes in the intensity of ethidium bromide fluorescence. Monoinfection with hepatitis B and C viruses was not accompanied by considerable changes in DNA structure in peripheral blood lymphocytes from patients with chronic diseases. The incidence of DNA damages in lymphocytes increased in patients with hepatitis G virus and TTV monoinfection. This is probably related to replication of these viruses in nucleated blood cells. Our results suggest that hepatitis C virus potentiates damaging effect of hepatitis G virus on DNA in lymphocytes.     

Mitochondrial biogenesis during the activation of lymphocytes by mitogens: the immunosuppressive action of tetracyclines

The role of mitochondrial biogenesis and function during mitogenic stimulation of rat thymocytes was investigated. The results show that mitochondrial biogenesis is required to provide the ATP for the energy-requiring processes occurring during blastogenesis. Impairment of mitochondrial biogenesis by inhibition of mitochondrial protein synthesis inhibits blast transformation. Since the tetracyclines impair mitochondrial protein synthesis, the results offer an explanation for the well-known immunosuppressive effects of these antibiotics.     

Correlation between cytotoxic T lymphocytes and suppressors blocking activation of DNA synthesis in mixed lymphocyte cultures

A parallel study was made of cytotoxic T lymphocytes (CTL) and suppressors induced by immunization in the H-2 system and inhibiting the activation of DNA synthesis in mixed cultures. Unlike the CTL, the suppressors do not adhere specifically to a monolayer of target cells, are not inactivated by treatment with anti- serum and complement, and their action is nonspecific: They inhibit the activation of DNA synthesis induced by any stimulator cells whatsoever and also by phytohemagglutinin and concanavalin A. CTL and suppressors are different populations of effector cells which can be separated from each other.Laboratory of Immunochemistry and Diagnosis of Tumors and Laboratory of Chemistry and Biochemistry of Antibodies, N. F. Gamaleya Institute of Epidemiology and Microbiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR P. A. Vershilova.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 2, pp. 189–192, February, 1978.     

Hydrogen peroxide-induced DNA damage and DNA repair in lymphocytes from malnourished children

The aim of this study was to assess DNA repair capacity in lymphocytes of children with protein calorie malnutrition using the single-cell gel electrophoresis (comet) assay. Repair capacity was assessed by estimating the relative decrease of DNA migration length 5, 15, 30, and 60 min after hydrogen peroxide treatment, in three groups of children: well-nourished (WN), well-nourished infected (WN-I), and malnourished infected (MN-I). In addition, the DNA migration length was evaluated in all groups before and after peroxide treatment. Comparison of mean migration lengths observed in WN and WN-I children showed significant differences at all times tested; between WN-I and MN-I differences were also observed, except after hydrogen peroxide exposure. This implies that lymphocytes of WN-I and MN-I children were equally sensitive to hydrogen peroxide. Nevertheless, the MN-I group clearly shows the greatest overall percentage of damaged cells at all times tested. In relation to repair capacity, at 5 min it was approximately 30% in both groups of well-nourished children, but only 20% in MN-I; 15 min after exposure, repair capacity increased to 51% in well-nourished children but only to 31% in MN-I; and at 60 min this capacity increased to 82% in well-nourished but only to 55% in MN-I. These data indicate that lymphocytes of malnourished children show a decreased capacity to repair hydrogen peroxide-induced DNA damage compared to that of well-nourished controls. This reflects that only malnutrition is associated with decreased DNA repair capacity. Additionally, the data confirm that severe infection and malnutrition are two factors clearly associated with increased DNA damage.     

连翘提取物对小鼠T淋巴细胞体外活化与增殖的影响

目的:分析连翘(FS)提取物对小鼠淋巴结T细胞的体外活化与增殖的影响,初步探讨其免疫抑制作用机制.方法:无菌分离小鼠淋巴结细胞,加入多克隆刺激剂刀豆蛋白A(ConA)进行刺激,利用荧光标记的单克隆抗体(mAb)染色结合流式细胞术(FCM),检测小鼠T淋巴细胞的表达的活化抗原CD69、CD25、CD71的表达情况;以羧基荧光素乙酰乙酸琥珀酰亚胺酯(CFDA-SE)染色,以FCM分析FS对淋巴细胞体外增殖的影响.结果:终浓度为40、80、160 mg/L的FS均对ConA刺激诱导的T细胞CD69、CD25和CD71的表达有降低作用(P＜0.05).CFDA-SE染色分析显示,上述浓度的FS对ConA诱导的小鼠T淋巴细胞增殖具有抑制作用(P＜0.05).结论:FS对ConA诱导的T细胞早、中、后期活化和体外增殖有抑制作用.     

The role of mitogens and antigens in the generation of antibody-producing human B lymphocytes

Satisfactory experimental systems with which to study the antigen specific humoral immune response of human peripheral blood lymphocytes have not been available until recently. A commonly used method for the study of antibody production by human lymphocytes is that developed by Fauci and Pratt. This system is considered to be antigen nonspecific since the antigen against which the determined antibody is directed is not added to the cultures. We show here that the assumption of the Fauci-Pratt system being antigen nonspecific is not justified. An essential ingredient of this culture system is human serum that has been exhaustively absorbed with antigen (sheep red blood cells). This absorption procedure causes shedding of highly immunogenic antigenic fragments whose immunogenic activity we demonstrated using a recently developed antigen-dependent culture system. In the latter system, we have shown that the control of suppressor cells is a critical factor for the successful induction of antibody responses, particularly in view of the fact that lymphocyte mitogens must be added to cultured human lymphocytes to support their responsiveness. Appropriate timing of mitogen addition to the cultures was found to be an effective means of preferentially stimulating helper or suppressor activity. Pokeweed mitogen, a mitogen known to act on B and on T lymphocytes, stimulates B-cell responses readily but abrogates them prematurely by the simultaneous activation of suppressor cells. When pokeweed mitogen is added to an ongoing response with a delay of 48 hr, it enhances antibody responses markedly, presumably by providing additional help to B cells at a time when they have lost susceptibility to suppressor-cell effects.