A Role for Activated Macrophages in Resistance to Infection with
            <i>Toxoplasma</i>

Remington, Jack S.; Krahenbuhl, James L.; Mendenhall, Joy W.

doi:10.1128/iai.6.5.829-834.1972

Cited by 130 publications

(54 citation statements)

References 5 publications

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“…The protection induced by such transfer is immunologically specific (13), which is consistent with our present understanding of thymus-dependent lymphocytes and their role in cellular immune mechanisms (2,16) . Macrophages from immunized animals have been described as "activated," and they have displayed enhanced ability to control in vitro infection of toxoplasmas as well as of immunologically unrelated organisms (17,18) . A clinical correlate of these observations is the fact that toxoplasmosis in humans is a particularly severe disease in those with depressed cellular immune mechanisms in spite of high antitoxoplasma antibody titers .…”

Section: Effects On Toxoplasma Multiplication In Macrophages Of Supermentioning

confidence: 99%

Assessment in vitro of immunity against Toxoplasma gondii.

Jones¹,

Len²,

Hirsch³

1975

The Journal of Experimental Medicine

134

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Studies have been made on humoral and cellular immune respones in mice immunized with an attenuated strain of Toxoplasma gondii. Heat-inactivated antitoxoplasma serum did not cause morphologic changes in the organisms, but did markedly influence their interactions with host cells. Toxoplasma exposed to antibody were no longer capable of entering fibroblasts or HeLa cells. They were readily engulfed by macrophages, but the antibody treatment strikingly altered the intracellular fate of the parasites leading to killing and digestion of the toxoplasmas in phagolysosomes. Addition of antitoxoplasma antibody immediately after infection of macrophages in vitro had no effect on intracellular multiplication of the organism. The division time of virulent toxoplasmas in mouse peritoneal macrophages in vitro was markedly prolonged in cells from immunized mice. During the first 2-3 mo after immunization, the macrophages harvested from the peritoneal cavity demonstrated this cellular immunity directly; thereafter exposure of the macrophages to immune lymphocytes and toxoplasma antigen, or to supernates from such an interaction was required for induction of the maximal capacity to inhibit growth of toxoplasmas. Induction of the alternation in macrophages by the lymphocyte product was detectable in 6 h and maximal at 18-24 h. Cultivation in vitro of macrophages from immunized animals for periods longer than 48 h rendered the cells nonresponsive to the immune lymphocyte-toxoplasma product. Macrophages from the peritoneal cavities of normal, nonimmunized mice were also incapable of developing the capacity to inhibit growth of toxoplasmas in response to this product. The nonresponsiveness of normal macrophages, or of macrophages cultured for several days in vitro was not changed by exposure of the cells to antitoxoplasma serum.

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Section: Effects On Toxoplasma Multiplication In Macrophages Of Supermentioning

confidence: 99%

Assessment in vitro of immunity against Toxoplasma gondii.

Jones¹,

Len²,

Hirsch³

1975

The Journal of Experimental Medicine

134

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“…A jor component of the host's defense mechanism against toxoplasmosis in vivo (4,19,26) and in vitro (2, 22,25), the humoral immune response appears to play at least some part in the host's response to the parasite. Specific antibody slows down parasite growth when added to tissue culture (1,15,26) and rapidly destroys tachyzoites in the presence of complement in vitro (23).…”

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confidence: 99%

Monoclonal Antibodies to Toxoplasma Cell Membrane Surface Antigens Protect Mice from Toxoplasmosis^1,2

Johnson

McDonald

Neoh

1983

The Journal of Protozoology

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Groups of mice were given an intraperitoneal injection of one of six monoclonal antibodies to Toxoplasma gondii, a mixture of equal amounts of five monoclonal antibodies to T. gondii, or the murine myeloma protein MOPC 21, and challenged with either a highly virulent or moderately virulent parasite strain. Two monoclonal antibodies (FMC 19 and FMC 22) conferred total protection against the moderately virulent challenge, with all mice surviving, whereas 90% of control mice died. FMC 19 and FMC 22 also conferred significant protection against the highly virulent challenge as indicated by a prolonged mean time to death (MTD) of immunized compared with control groups of mice. One monoclonal antibody (FMC 23) and the mixture of five antibodies gave significant protection against the moderately virulent challenge only. Passive immunization with dilutions of FMC 22 antibody indicated that the lowest serum titer needed to confer significant protection to mice against a moderately virulent Toxoplasma challenge was 1/640. Mice challenged with highly virulent tachyzoites that had been preincubated with FMC 22 had a significantly longer MTD than mice challenged with highly virulent tachyzoites that had been preincubated with MOPC 21 or phosphate buffered saline, pH 7.2 (PBS). Immunoprecipitation and autoradiography of radiolabeled tachyzoites confirmed that FMC 19 was directed against a 35,000 molecular weight (mol. wt.) antigen and FMC 22 was directed against a 14,000 mol. wt. fraction. The potential for use of single antigens as protective immunogens in preventing toxoplasmosis is raised.

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“…The importance of activated macrophages as effectors of immune protection to infection with Toxoplasma gondii has been well established (13,16). However, the mechanism whereby the cells acquire the enhanced ability to inhibit or kill this parasite is still unclear .…”

mentioning

confidence: 99%

Production and Properties of Immune Interferon from Spleen Cell Cultures of Toxoplasma‐Infected Mice

Shirahata

Shimizu

1980

Microbiology and Immunology

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In response to antigenic stimulation, spleen cells from Toxoplasmainfected mice produce a factor showing inhibitory activity against vesicular stomatitis virus infection in L cell cultures. When BALB/C and ICR mice were inoculated intraperitoneally with the low-virulent S-273 strain of T. gondii, such activity was first detected in 4 and 7 days and reached maximum levels at 10 and 14 days respectively, and retained these levels for at least three weeks. However, BALB/C mice, which are considerably more sensitive to Toxoplasma infection than ICR mice, produced significantly smaller amounts of interferon (IF) after challenge with the high virulent strain.The IF produced in this system possessed certain known properties of immune (type II) IF and was not neutralized by rabbit antiserum against mouse type I IF. The immune IF preparation also inhibited multiplication of Toxoplasma within nonphagocytic L cells in an IF-like fashion, whereas Newcastle disease virusinduced (type I) IF had no effect on this parasite. The antiviral and anti-Toxoplasma activity in immune IF preparations could not be distinguished solely on the bases of their molecular weight and isoelectric point. The experiments with anti-0 serum plus complement and with nylon wool column effluent cells strongly suggest that immune IF was produced by T lymphocytes and required the assistance of macrophages.

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A Role for Activated Macrophages in Resistance to Infection with Toxoplasma

Cited by 130 publications

References 5 publications

Assessment in vitro of immunity against Toxoplasma gondii.

Assessment in vitro of immunity against Toxoplasma gondii.

Monoclonal Antibodies to Toxoplasma Cell Membrane Surface Antigens Protect Mice from Toxoplasmosis^1,2

Production and Properties of Immune Interferon from Spleen Cell Cultures of Toxoplasma‐Infected Mice

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A Role for Activated Macrophages in Resistance to Infection with Toxoplasma

Cited by 130 publications

References 5 publications

Assessment in vitro of immunity against Toxoplasma gondii.

Assessment in vitro of immunity against Toxoplasma gondii.

Monoclonal Antibodies to Toxoplasma Cell Membrane Surface Antigens Protect Mice from Toxoplasmosis1,2

Production and Properties of Immune Interferon from Spleen Cell Cultures of Toxoplasma‐Infected Mice

Contact Info

Product

Resources

About

Monoclonal Antibodies to Toxoplasma Cell Membrane Surface Antigens Protect Mice from Toxoplasmosis^1,2