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Copyright of Acta Pediatrica de Mexico is the property of Instituto Nacional de Pediatria (INP) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Pediatrica de Mexico is the property of Instituto Nacional de Pediatria (INP) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Pediatrica de Mexico is the property of Instituto Nacional de Pediatria (INP) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Toxoplasma gondii infection can trigger autoreactivity by different mechanisms. In the case of ocular toxoplasmosis, disruption of the blood-retinal barrier may cause exposure of confined retinal antigens such as recoverin. Besides, cross-reactivity can be induced by molecular mimicry of parasite antigens like HSP70, which shares 76% identity with the human ortholog. Autoreactivity can be a determining factor of clinical manifestations in the eye and in the central nervous system. We performed a prospective observational study to determine the presence of autoantibodies against recoverin and HSP70 by indirect ELISA in the serum of 65 patients with ocular, neuro-ophthalmic and congenital cerebral toxoplasmosis. We found systemic autoantibodies against recoverin and HSP70 in 33.8% and 15.6% of individuals, respectively. The presence of autoantibodies in cases of OT may be related to the severity of clinical manifestations, while in cases with CNS involvement they may have a protective role. Unexpectedly, anti-recoverin antibodies were found in patients with cerebral involvement, without ocular toxoplasmosis; therefore, we analyzed and proved cross-reactivity between recoverin and a brain antigen, hippocalcin, so the immunological phenomenon occurring in one immune-privileged organ (e.g. the central nervous system) could affect the environment of another (egg. the eye). [ABSTRACT FROM AUTHOR]

Toxoplasma gondii is the etiological agent of toxoplasmosis. Mother-to-child transmission of this parasite can occur during pregnancy. Newborns with congenital toxoplasmosis may develop central nervous system impairment, with severity ranging from subclinical manifestations to death. A proinflammatory/regulated specific immune profile is crucial in the defense against the parasite; nevertheless, its role in the infected pregnant women and the congenitally infected offspring has been poorly explored, and there is still no consensus about its relation to parasite vertical transmission or to severity and dissemination in the congenitally infected newborns. This work aimed to characterize these relations by means of principal component and principal factor analyses. For this purpose, we determined the specific production of the four immunoglobulin G antibody subclasses, cytokines, and lymphocyte proliferation in the T. gondii– infected pregnant women−10 who transmitted the infection to their offspring and seven who did not—as well as in 11 newborns congenitally infected and grouped according to disease severity (five mild and six moderate/severe) and dissemination (four local and seven disseminated). We found that the immune response of nontransmitter women differed from that of the transmitters, the latter having a stronger proinflammatory response, supporting a previous report. We also found that newborns who developed moderate/severe disease presented higher levels of lymphocyte proliferation, particularly of CD8+ and CD19+ cells, a high proportion of tumor necrosis factor α producers, and reduced expression of the immune modulator transforming growth factor β, as opposed to children who developed mild clinical complications. Our results suggest that a distinctive, not regulated, proinflammatory immune response might favor T. gondii vertical transmission and the development of severe clinical manifestations in congenitally infected newborns. [ABSTRACT FROM AUTHOR]

Toxoplasmosis is a parasitic zoonosis distributed worldwide, caused by the ingestion of contaminated water/food with the parasite Toxoplasma gondii. If a pregnant woman is infected with this parasite, it may be transmitted to the fetus and produce ocular, neurological, or systemic damage with variable severity. The strength and profile of mother's immune response have been suggested as important factors involved in vertical transmission rate and severity of clinical outcome in the congenitally infected fetus. The aim of this work was to evaluate a possible relation between the mother's immune response during pregnancy and congenital transmission to the fetus. We obtained peripheral blood from T. gondii infected pregnant woman and tested it for anti T. gondii (IgG1, IgG2, IgG3, IgG4, and IgA) in serum. Peripheral blood mononuclear cells (PBMCs) were isolated to analyze the in vitro effect of soluble T. gondii antigens on proliferation and production of cytokines. We found that IgG2-4 and IgA antibodies and lymphocytes proliferation, especially CD4+, CD8+, and CD19+ were positive in a higher proportion of cases in transmitter than in non-transmitter women. Furthermore, IgG2-3 and IgA anti- Toxoplasma antibody levels were higher in those mothers who transmitted the infection than in those who did not. Interestingly, a higher proportion of positive cases to IFN-γ and negatives to the immunoregulatory cytokine TGF-β, were related to T. gondii vertical transmission. Our descriptive results are consistent with the paradoxical previous observations in murine models of congenital toxoplasmosis, which suggest that an increased immune response that protects the mothers from a disseminated or severe disease, and should protect the fetus from infection, is positively related to parasite transmission. [ABSTRACT FROM AUTHOR]

Copyright of Acta Pediatrica de Mexico is the property of Instituto Nacional de Pediatria (INP) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Toxoplasma gondii is among the commonest zoonotic infectious agents worldwide. It infects many warm-blooded animals, including felines, the definitive hosts. This parasite is now classified in 15 haplogroups spread out around the world. Few reports reveal a predominance of genotypes I and III in Mexico, although recombinant and atypical variants have also been found in humans and animals. The aim of this study was to detect, isolate and genotype T. gondii from cats of Colima Mexico, and to analyze tissue distribution of the parasite. IgG specific antibodies were investigated in 48 serum samples from unwanted and stray cats by indirect ELISA. Isolation in mice and molecular characterization by PCR-RFLP and sequencing were attempted using pools of brain, heart, liver, lung, spleen and brachiocephalic muscle samples of seropositive cats. Fourteen animals (29.2%) were seropositive, the frequency ranged between 27.3 and 40% among the different localities. Ten seropositive animals were euthanized, eight of them were positive for the B1 gene by conventional PCR. More frequently infected tissues were the brachiocephalic muscle (75.0%) the brain (63.0%) and the spleen (63.0%). Genotype III was determined for the SAG3 locus of the parasite infecting an unwanted cat. Tachyzoites were isolated from the peritoneal cavity of two mice inoculated with the tissue pool of one kitten. Type I alleles were found in SAG1 , SAG2 , SAG3 , BTUB , GRA6 , c29-2 and PK1 loci, while c22-8 was type II, and L358 and Apico were type III. This genotype corresponds to ToxoDB genotype #28. This is the first T. gondii isolate genetically characterized in Colima, Mexico and is different to other isolations of the country. [ABSTRACT FROM AUTHOR]

Abstract: In order to determine the frequency of anti-Toxoplasma gondii IgG antibodies in domestic cats and to identify the possible risk factors, 169 domestic cats from 16 municipalities of Mexico City were studied. Their serum was tested by indirect ELISA and the owners answered a questionnaire about age, gender, litter box hygiene, contact with other cats, housing (indoor, outdoor) and diet. We found 37 (21.8%) seropositive cats to T. gondii with an increase in frequency related to age. Main risk factors were female gender, feeding the pet with raw meat and infrequent cleaning of the litter box. The frequency of T. gondii antibodies found in domestic cats of Mexico City suggests active transmission within an urban environment. [Copyright &y& Elsevier]