<u>Mycoplasma Neurolyticum</u>Membranes: A T-Independent Antigen in the Rat

Kaplan, Phyllis-Jean; Garvey, James E.

doi:10.3109/08820138609042017

Cited by 6 publications

(8 citation statements)

References 31 publications

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“…As summarized in Table 5, mycoplasmas are mitogenic toward B lymphocytes, T lymphocytes, or both B and T lymphocytes. Generally, proliferation of B lymphocytes, induced by mitogenic mycoplasmas in vitro, did not require the presence of accessory cells (91,212,309). In contrast, accessory cells were essential for M. arginini-induced mouse B-cell activation (397) and were crucial for the interactions of M. arthritidis with human and mouse T cells (91).…”

Section: Activation Of Immune Cells By Mitogenic Mycoplasmasmentioning

confidence: 99%

Molecular Biology and Pathogenicity of Mycoplasmas

Razin

Yogev

Naot

1998

Microbiol Mol Biol Rev

1,457

954

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SUMMARY The recent sequencing of the entire genomes of Mycoplasma genitalium and M. pneumoniae has attracted considerable attention to the molecular biology of mycoplasmas, the smallest self-replicating organisms. It appears that we are now much closer to the goal of defining, in molecular terms, the entire machinery of a self-replicating cell. Comparative genomics based on comparison of the genomic makeup of mycoplasmal genomes with those of other bacteria, has opened new ways of looking at the evolutionary history of the mycoplasmas. There is now solid genetic support for the hypothesis that mycoplasmas have evolved as a branch of gram-positive bacteria by a process of reductive evolution. During this process, the mycoplasmas lost considerable portions of their ancestors’ chromosomes but retained the genes essential for life. Thus, the mycoplasmal genomes carry a high percentage of conserved genes, greatly facilitating gene annotation. The significant genome compaction that occurred in mycoplasmas was made possible by adopting a parasitic mode of life. The supply of nutrients from their hosts apparently enabled mycoplasmas to lose, during evolution, the genes for many assimilative processes. During their evolution and adaptation to a parasitic mode of life, the mycoplasmas have developed various genetic systems providing a highly plastic set of variable surface proteins to evade the host immune system. The uniqueness of the mycoplasmal systems is manifested by the presence of highly mutable modules combined with an ability to expand the antigenic repertoire by generating structural alternatives, all compressed into limited genomic sequences. In the absence of a cell wall and a periplasmic space, the majority of surface variable antigens in mycoplasmas are lipoproteins. Apart from providing specific antimycoplasmal defense, the host immune system is also involved in the development of pathogenic lesions and exacerbation of mycoplasma induced diseases. Mycoplasmas are able to stimulate as well as suppress lymphocytes in a nonspecific, polyclonal manner, both in vitro and in vivo. As well as to affecting various subsets of lymphocytes, mycoplasmas and mycoplasma-derived cell components modulate the activities of monocytes/macrophages and NK cells and trigger the production of a wide variety of up-regulating and down-regulating cytokines and chemokines. Mycoplasma-mediated secretion of proinflammatory cytokines, such as tumor necrosis factor alpha, interleukin-1 (IL-1), and IL-6, by macrophages and of up-regulating cytokines by mitogenically stimulated lymphocytes plays a major role in mycoplasma-induced immune system modulation and inflammatory responses.

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Section: Activation Of Immune Cells By Mitogenic Mycoplasmasmentioning

confidence: 99%

Molecular Biology and Pathogenicity of Mycoplasmas

Razin

Yogev

Naot

1998

Microbiol Mol Biol Rev

1,457

954

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“…A soluble toxin, probably a lipoglycan, causes the disease (Smith 1987. M. neurolyticum is mitogenic for murine lymphocytes in vitro (Naot et al 1977); the responsible compound has been identified to be a lipoglycan (Kaplan & Garvey 1986). It is worth nothing that mice injected with tumor-necrosis factor (TNF) and mycoplasma-infected cell lines develop a hemorrhagic necrosis while mice injected with Gram-negative bacteria or LPS develop lethal shock (Rothstein & Schreiber 1988).…”

Section: Mycoplasma Effects On Lymphocytes In Vivomentioning

confidence: 99%

“…neurolyticum is capable, in vitro, of activating B cells, from both mice and rats, in a T-cel! independent way (Kaplan & Garvey 1986, Naot et al 1977, 1979c, Naot & Ginsburg 1978, Smith 1987. The active compound is located on the membrane (Naot et al 1979c, Kaplan & Garvey 1986) and has been identified as being a lipoglycan or lipopolysaccharide (LPS) (Kaplan & Garvey 1986).…”

Section: Effects Of Mycoplasmas On B Lymphocytes In Vitromentioning

confidence: 99%

“…independent way (Kaplan & Garvey 1986, Naot et al 1977, 1979c, Naot & Ginsburg 1978, Smith 1987. The active compound is located on the membrane (Naot et al 1979c, Kaplan & Garvey 1986) and has been identified as being a lipoglycan or lipopolysaccharide (LPS) (Kaplan & Garvey 1986). It is noteworthy that LPS from mycoplasmas are different from the LPS found in Gram-negative bacteria in that they do not possess the hpid A structure (Barile et al 1979, Smith 1987; in fact, mycoplasma LPS is a poor inducer of fever in rabbits and is inactive in the Limulus amebolysate clotting test (Weinberg et al 1980).…”

Section: Effects Of Mycoplasmas On B Lymphocytes In Vitromentioning

confidence: 99%

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Interactions between Mycoplasmas and the Immune System

Ruuth

Praz

1989

Immunological Reviews

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Mycoplasmas are a heterogenous group of prokaryotic organisms causing a wide variety of diseases, including autoimmune disorders. Thus, it is not surprising that various mycoplasmas strains, including Mycoplasma arginini, M. arthritidis, M. neurolyticum and M. pulmonis, are able to regulate the immune response. Though some of the studies of the immunomodulatory action of mycoplasmas have been done in vivo, the majority of the investigations have been conducted in vitro. This has led to the recognition that mycoplasmas are polyclonal activators of both B and T cells from several species, acting through MHC-restricted or -unrestricted pathways. Mycoplasma activation not only induces T-cell proliferation but also leads but to the formation of cytotoxic T cells. We, as well as others, have shown that mycoplasma-mediated B-cell activation induces proliferation as well as Ig secretion, and also that mycoplasma stimulation of lymphocytes may result in the production of cytokines. We communicate here our investigations into the effects of an M. arginini strain on the growth and maturation of preactivated B cells. After an initial biological characterization of the M. arginini effects in vitro, we established the protein nature of the growth-supporting activity and proceeded further on to isolate and identify the responsible proteins. The use of lipid- and lipoglycan-free extracts has allowed us to further extend our studies on the biological activities of the proteins from M. arginini and to compare these results with the effects obtained using live organisms. Furthermore, the study was extended to include a characterization of the in vivo-induced effects of live M. arginini. Altogether, the results from these experiments allow us to conclude that M. arginini is a T-cell independent polyclonal B-cell mitogen, mediated by five identified proteins, inducing growth and Ig secretion of both resting and preactivated B cells.

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“…Generally, proliferation of B lymphocytes, induced by mitogenic mycoplasmas in vitro, did not require the presence of accessory cells (91,212,309). In contrast, accessory cells were essential for M. arginini-induced mouse B-cell activation (397) and were crucial for the interactions of M. arthritidis with human and mouse T cells (91).…”

Section: Activation Of Immune Cells By Mitogenic Mycoplasmasmentioning

confidence: 99%

Molecular Biology and Pathogenicity of Mycoplasmas

2002

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Mycoplasma NeurolyticumMembranes: A T-Independent Antigen in the Rat

Cited by 6 publications

References 31 publications

Molecular Biology and Pathogenicity of Mycoplasmas

Molecular Biology and Pathogenicity of Mycoplasmas

Interactions between Mycoplasmas and the Immune System

Molecular Biology and Pathogenicity of Mycoplasmas

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