Mycoplasma Mimicry of Lymphokine Activity in T‐Cell Lines

Scandinavian Journal of Immunology, 1986

B lymphocytes, preactivated by lipopolysaccharide (LPS), could he triggered to growth by a strain of Mycoplasma arginini, while the level of immunoglobulin (Ig) secretion, quantitatesd as the number of plaque-forming cells (PFC). was low. The PFC response could be increased by the addition of conditioned media (CM) from lectin-activated spleen cells or T cell tumour EL.-4 to the culture of preactivated B cells. CM did not by itself induce a significant amount of PFC in the cultures of LPS-preactivated B cells. The maturation enhancing activity was distinct from 1L-2 and B cell growth factor as judged by gel exclusion chromatography.

Human Immunology, 1984

We have produced two monoc/onal antibodies. SFR l-Myco 1 and SFR 1-Myco 2. that detect Mycoplasma fermentans Jound to contaminate/ymphoblastoid cell lines (LCL). The specifici(y of these monodonal antibodies against the M. fermentans was determined by indirect immunofluorescence by demonstrating the reactivity of the monoc/onal antibodies with known re]erence strains of mycoplasma grown on soft agar. The reactivity of these antibodies against LCL in a number of immunoassays correlates completely with the presence of mycop/asma in these ce/i~ as determined by a standard mycoplasma detection assa). Because of the potential for ,'idespread contamination of B [ymphoblastoid cell lines tranfformed with Epstein-Barr virus-containing supernatants obtained from marmoset call lines contaminated with M. fermentans, these monoc/ona/ antibodies have value as screening reagents .fi)r this no'cop/asma species in LCL. ABBREVIATIONS LCL lymphoblastoid cell line PBA HAT hypoxanthine-aminopterinthymidine BLCL B lymphoblastoid cell line FACS EBV Epstein-Barr virus phosphate buffered saline, pH v.4, 2'7~ bovine serum albumin, 0.02(7{ sodium azide fluorescence-activated cell sorter

The Journal of Immunology

Mycoplasma arginini, when grown in broth or in cultures of human lymphoblast cell lines, inhibits activation of lymphocytes by allogeneic cells of mitogens. This inhibition can also be produced by cell free media obtained after the growth of this organism. Inhibition is not species specific and inhibits both B and T cell activation in the mouse. The inhibitory factor is required during the first 3 days of the mixed leukocyte culture, but has no effect on the latter phase of this reaction when thymidine uptake is greatest. The factor is stable to treatment at 60°, but not 90°, for 30 min.

Infection and immunity, 1985

The synthesis and secretion of immunoglobulin M (IgM), as well as the relative ratio of membrane and secretory mu heavy chain (mu m and mu s, respectively), were evaluated in mycoplasma-contaminated B lymphoblastoid cell lines. The ratio of mu m to mu s was drastically lowered in infected cultures, and mu s chains could now combine with light chains. A 50 to 100% increase in IgM synthesis occurred in contaminated cultures, and small amounts of IgM were detectable in the culture media. These molecules possessed mu chains typical of secreted IgM. Reexpression of mu on the surface of B lymphoblastoid cells was substantially delayed in mycoplasma-contaminated cultures. Thus, mycoplasma contamination alters the synthesis and expression of a specific differentiated gene product (immunoglobulin) in B cell lines; such changes could significantly affect the interpretation of data on immunoglobulin synthesis by B cells with different phenotypes. This system may also provide a means of studyin...

Journal of Immunological Methods, 1988

Tiamuline and minocycline were evaluated for the treatment of an IgM producing human-human hybridoma cell line infected with Mycoplasma hyorhinis. Tiamuline was used at a concentration of 10 /~g/ml culture medium and minocycline at a concentration of 5 ~g/ml culture medium. Both antibiotics were found to eliminate mycoplasma infection over a treatment period of 3 weeks, and the hybridoma cell line remained mycoplasma-free for 6 months after treatment. Tiamuline had no effect on either cell growth or IgM secretion. Whereas treatment with minocycline alternated the cell proliferation and completely inhibited IgM secretion. This effect on cell function was found to be reversible since both cell growth and IgM secretion returned to normal 1 week after the minocycline had been removed. Tiamuline as well as minocycline may be recommended for the treatment of human hybridomas infected with mycoplasma.

Brazilian Journal of Microbiology, 2014

Mycoplasma spp, belongs to the class Mollicutes and is capable to produce alterations in cellular cultures causing damages to the biotechnological industry. Bioproducts generally require two essential inputs, bovine serum and cells. The study herein aims to evaluate the mycoplasma concentrations that affect the growing of BHK21 and Vero cells. The species used were: Mycoplasma orale, M. salivarium, M. arginini and M. hyorhinis, cultivated in a SP4 media. Two contamination tests were performed with BHK21 and Vero cells and one of them applied different concentrations of mycoplasma. In the first one, mycoplasma was applied at the day zero and, in the second one, the contamination was performed after the monolayer establishment. The both cellular cultures presented cytopathic effects with mycoplasma contamination, but the Vero cells suffered more damages than the BHK21 ones. It was also observed that the severity of the cytopathic effect depended on the mycoplasma specie, on the concentration and on the time of contact with the cellular culture, which evidences the importance of controlling the presence of mycoplasma in biotechnological industries.

1988

Immune responses are the result of extended clonal growth and maturation of specific precursors preexisting in low frequencies. Clonal expansion is partly controlled by soluble factors, thus, their ...

In Vitro, 1984

Infection of cell cultures by mycoplasmas can be detected and the mycoplasma identified by Southern blot hybridization of the Eco RI-digested DNA of the suspected cell cultures with a nick-translated probe consisting of cloned ribosomal RNA genes of Mycoplasma capricolum. The probe does not hybridize with eukaryotic DNA. The hybridization pattern with mycoplasmal DNA is species specific, enabling the identification of the four most prevalent mycoplasma contaminants, Mycoplasma orale, Mycoplasma hyorhinis, Mycoplasma arginini, and Acholeplasma laidlawii. The test is also very sensitive and can detect as little as 1 ng of mycoplasmal DNA, roughly equivalent to the DNA content of l0 s mycoplasmas.

PLOS One, 2011

Background: Mesenchymal stromal cells (MSC) have important immunomodulatory effects that can be exploited in the clinical setting, e.g. in patients suffering from graft-versus-host disease after allogeneic stem cell transplantation. In an experimental animal model, cultures of rat T lymphocytes were stimulated in vitro either with the mitogen Concanavalin A or with irradiated allogeneic cells in mixed lymphocyte reactions, the latter to simulate allo-immunogenic activation of transplanted T cells in vivo. This study investigated the inhibitory effects of rat bone marrow-derived MSC subsequently found to be infected with a common mycoplasma species (Mycoplasma hyorhinis) on T cell activation in vitro and experimental graft-versus-host disease in vivo.

Veterinary Microbiology, 2000

The 36 kDa L-lactate dehydrogenase (LDH) and a 29 kDa partial fragment of an ABC transporter ATP-binding protein analogue/multidrug resistance protein homologue (PR2) of Mycoplasma hyopneumoniae were tested for their potential as diagnostic antigens. Recombinant LDH was genetically engineered to contain six histidine residues at its C-terminal end, expressed in Escherichia coli and puri®ed to a high degree using Ni 2 -chelate af®nity chromatography. A partial 262 amino acid segment representing the C-terminal end of the PR2 protein was cloned as a glutathione S-transferase (GST) fusion protein, expressed in E. coli and puri®ed by urea extraction. Puri®ed recombinant LDH±6ÂHis and PR2-GST were then reacted with pig sera in immunoblot assays. Our immunoblots showed that both proteins detected anti-M. hyopneumoniae antibodies in ®eld and experimentally infected pig sera but not in any of the SPF control sera. The two proteins were speci®c for M. hyopneumoniae as they did not react with sera of pigs infected with the closely related Mycoplasma¯occulare and Mycoplasma hyorhinis which are frequently isolated in pigs but are not of particular concern. #