ORCID Profile
0000-0003-2427-7699
Current Organisations
Fundação Oswaldo Cruz
,
University of Massachusetts Medical School
,
Universidade Federal de Minas Gerais
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Publisher: American Society for Microbiology
Date: 09-2011
DOI: 10.1128/IAI.05048-11
Abstract: Apical membrane antigen 1 (AMA-1) is an invasion-related Plasmodium antigen that is expressed during both intracellular and extracellular asexual stages of the parasite's life cycle, making it an ideal target for induction of humoral and cellular immune responses that can protect against malaria. We show here that when it is administered as a recombinant protein (P) in Montanide ISA720 adjuvant, followed by a recombinant human type 5 adenovirus (Ad), intense and long-lasting Plasmodium vivax AMA-1-specific antibody responses (including both IgG1 and IgG2a), as well as proliferative memory T cell responses, can be detected in immunized mice. Memory T cells displayed both central (CD44 hi CD62L hi ) and effector (CD44 hi CD62L lo ) phenotypes, with the central memory phenotype prevailing (56% of AMA-1-specific proliferating cells). Considering the main traits of the memory immune responses induced against AMA-1, this particular sequence of immunogens (P followed by Ad), but no others (Ad/Ad, Ad/P, or P/P), displayed an optimal synergistic effect. These results give further support to the need for preclinical studies of P. vivax vaccine candidate AMA-1 administered in prime/boost protocols that include recombinant proteins and adenoviral vectors.
Publisher: American Society for Microbiology
Date: 11-2003
DOI: 10.1128/IAI.71.11.6392-6401.2003
Abstract: Herein we characterized various genetic markers and the biological behavior of a natural recombinant strain of Toxoplasma gondii (P-Br). From nine genetic markers analyzed, three ( B1 , ROP1 , and SAG1 ) and three ( cS10-A6 , GRA6 , and SAG3 ) markers belong to parasites from the type I and type III lineages, respectively. The SAG2 and L363 loci were shown to be type I-III chimera alleles. The cB2l-4 microsatellite marker showed a unique haplotype. The P-Br strain presented low virulence in the acute phase of infection and was cystogenic during the chronic infection. The interleukin 12/gamma interferon axis and inducible nitric oxide synthase were main determinants of resistance during the acute infection with the P-Br strain. As opposed to infection with the type II strain of T. gondii (ME-49), peroral infection with the P-Br strain led only to a light inflammatory infiltrate and no major lesions in the intestine of the C57BL/6 mice. In addition, the BALB/c (resistant to ME-49) and C57BL/6 (susceptible to ME-49) mice were shown, respectively, to be more susceptible and more resistant to cyst formation and toxoplasmic encephalitis when infected with the P-Br strain. Further, the C57BL/KsJ and DBA2/J congenic strains containing major histocompatibility complex (MHC) haplotype “d” were more resistant than the parental strains (C57BL/6 and DBA1/J), when infected with the ME-49 but not with the P-Br strain. Together, our results indicate that resistance to cyst formation and toxoplasmic encephalitis induced during infection with P-Br is not primarily controlled by the MHC haplotype d, as previously reported for type II strains of T. gondii .
Publisher: Oxford University Press (OUP)
Date: 07-2004
DOI: 10.1086/421505
Publisher: American Society for Microbiology
Date: 04-2002
DOI: 10.1128/JCM.40.4.1400-1405.2002
Abstract: In the present study we developed an enzyme-linked immunosorbent assay (ELISA) to measure immunoglobulin M (IgM) specific for glycoinositolphospholipids (GIPL) derived from tachyzoite membrane (IgM-GIPL ELISA). The sensitivity and specificity of the assay were compared with those of commercially available Toxoplasma -specific IgM serological tests, namely, immunofluorescence assay (IFA) with fixed tachyzoites and capture ELISA employing tachyzoite extracts. Our results show that all patients with acute toxoplasmosis, as determined by clinical data and conventional serological tests, were also positive by the IgM-GIPL ELISA. Interestingly, many patients that were classified as indeterminate, who had IgG with high avidity but positive results in the IgM-specific IFA and capture ELISA, were negative by the IgM-GIPL ELISA. Finally, we tested the sera from patients with rheumatoid arthritis and various parasitic infections and found no evidence of false positives in the IgM-GIPL ELISA.
Publisher: Elsevier BV
Date: 2007
DOI: 10.1016/J.MICINF.2006.10.016
Abstract: Adhesion of Trypanosoma cruzi to host cells employs mechanisms which are complex and not completely understood. Upon infection, host cells release pro-inflammatory cytokines and chemokines in the environment. These had been found to be involved with increasing parasite uptake as well as killing by macrophages and cardiomyocytes. In the present study, we focused on the interaction of murine beta-chemokine CCL2 with trypomastigote forms of T. cruzi. We found that this chemokine directly triggers the chemotaxis and morphogenesis of trypomastigote forms of parasites. Binding assays showed that the interaction of CCL2 with molecules present in trypomastigote forms is abolished by the addition of condroitin 6-sulphate, a glycosaminoglycan. Moreover, we also observed that the parasite glycoproteins are the major players in this interaction. In summary, our study demonstrates a host ligand arasite receptor interaction that may have relevant implications in the tissue tropism of this important parasitic disease.
Location: United States of America
Location: United States of America
No related grants have been discovered for Ricardo Gazzinelli.