Plasmodium falciparum liver stage antigen-1 (PfLSA-1) is one of the few antigens expressed exclusively in liver stage parasites. In this study, we evaluated the antibody responses against recombinant PfLSA-1 in naturally infected individuals in Myanmar. High levels of antibody responses (70.7%) were detected in 82 serum samples from 116 infected individuals, and IgG responses to PfLSA-1 principally composed of responses of IgG1 and IgG3 subclasses. These results show that PfLSA-1 elicits effective antibody responses in individuals infected with P. falciparum, and thus it could be not only an attractive candidate protein for vaccine development, but also a useful antigen for serodiagnosis of the infection.
Animals ; Antibodies, Protozoan/*blood/immunology ; Antigens, Protozoan/*immunology ; Humans ; Immunoglobulin G/blood ; Malaria, Falciparum/blood/epidemiology/*immunology ; Myanmar/epidemiology

Excretory/secretory proteins (ESP) from Toxoplasma gondii were analyzed to define the function in the penetration process into host cells. Whole ESP obtained at 37 degrees C were composed of 15 bands with molecular mass of 110, 97, 86, 80, 70, 60, 54, 42, 40, 36, 30, 28, 26, 22, and 19 kDa. Five ESP of 86, 80, 42, 36, and 28 kDa were reacted with monoclonal antibodies (mAb), named as Tg386 (microneme), Tg485 (surface membrane), Tg786 (rhoptry), Tg378, and Tg556 (both dense granules), respectively. The ESP was released by a temperature-dependent/-independent manner and all at once whenever ready to pour out except Tg786. Each ESP was not exhausted within the parasite but the amount was limited. Tg786 was released continuously with increment, whereas Tg378 and Tg556 were ceased to release after 3 and 4 hr. Dense granular Tg378 and Tg556 were released spontaneously and constitutively before the entry into host cells also. The entry of T. gondii was inhibited by all the mAbs differentially. And the parasite deprived of ESP was inhibited to enter exponentially up to 90.1%. It is suggested that ESP play an essential function to provide appropriate environment for the entry of the parasite into host cells.
Animals ; *Antibodies, Monoclonal ; *Antibodies, Protozoan ; Antigens, Protozoan/*analysis/physiology ; Mice ; Mice, Inbred BALB C ; Support, Non-U.S. Gov't ; Temperature ; Toxoplasma/*chemistry/pathogenicity

OBJECTIVETo characterize the immune response induced by SAG1 encoding plasmid combined with IL-2 gene adjuvant in mice and to assess the protective effect of this vaccination against toxoplasmosis.

METHODSMice were co-injected intramuscularly with plasmid encoding Toxoplasma gondii SAG1 plus murine IL-2 expression vector at a dose of 100 microg. Booster immunizations were employed 2 more times at 3-week interval. As controls, mice were inoculated with PBS or empty plasmid pcDNA3. Humoral and cellular responses were assayed using ELISA for the determination of Ab, Ab isotype and IFN-gamma, as well as IL-4. To detect the integration and dissemination of DNA in the injected mice, PCR and in situ hybridization were performed. All mice were then infected with highly virulent RH tachyzoites of Toxoplasma gondii intraperitoneally.

RESULTSSignificant increases in specific IgG levels were observed in mice after immunization three times with SAG1 expression plasmid. With respect to the IgG isotype, co-inoculation of IL-2 expression plasmid enhanced the level of IgG2a and the production of IFN-gamma. Challenging mice by vaccinating with combined plasmids with RH tachyzoites resulted in prolonged survival.

CONCLUSIONHumoral and cytokine responses elicited by SAG1 DNA immunization can be modulated by co-inoculation with IL-2 expression plasmid. The use of DNA vaccine in combination with an appropriate cytokine gene to prevent T. gondii infection warrants further investigation.

Animals ; Antibodies, Protozoan ; blood ; Antigens, Protozoan ; Cytokines ; biosynthesis ; Female ; Immunization ; Immunoglobulin G ; blood ; classification ; Interleukin-2 ; genetics ; Mice ; Protozoan Proteins ; genetics ; Protozoan Vaccines ; immunology ; Toxoplasma ; immunology ; Toxoplasmosis, Animal ; prevention & control ; Vaccines, DNA ; immunology

OBJECTIVE: To investigate the infection rate of Toxoplasma gondii in patients with hematological diseases. METHODS: The Toxoplasma gondii IgM antibody in 200 patients with hematological diseases were tested, at the same time, IgM antibody in the persons received physical examination and other patients with common clinical diseases also were test, and their detection results were compared. RESULTS: The positive rate of Toxoplasma gondii IgM antibody in patients with hematological diseases was 7.50%, the positive rate in persons received physical examination was 0.67%, and the positive rate in patients with other common clinical diseases was 1.20%. The positive rate of IgM antibody in patients with hematological diseases was statistically significantly higher than that in the latter two kinds of persons(P<0.05). Among the patients with hematological diseases, the positive rate of Toxoplasma gondii IgM antibody in patients with bone marrow neoplastic diseases was 10.32%, which was statistically significantly higher than that in patients with bone marrow non-neoplastic diseases (2.70%). CONCLUSION Patients with hematological diseases are susceptible to Toxoplasma gondii, and to whom enough attention should be paid.
Antibodies, Protozoan ; Hematologic Diseases ; complications ; Humans ; Immunoglobulin G ; Immunoglobulin M ; Toxoplasmosis ; complications

Serum samples from three populations of Papua New Guinea, where Plasmodium falciparum malaria and human T-lymphotropic virus type 1 (HTLV-1) are coendemic at high prevalence rates, showed statistically significant ELISA co-seropositivity and co-seronegativity. Cross-reactivity was further indicated by the presence of 10 bands ranging from 134 kDa to 18 kDa on immunoblots of electrophoresed whole lysate P. falciparum antigen against serum of HTLV-1 seropositive patients from an area where malaria is not present. Similarly, sera from patients positive for human immunodeficiency virus (HIV) from a non-malarious region produced immunoblot bands ranging from 134 kDa to 33 kDa to the P. falciparum antigen. The HTLV-1 and HIV serum samples yielded a number of immunoblot bands when reacted to an electrophoresed human O type red cell membrane antigen, but those bands had no identity to the cross-reactive bands on the P. falciparum antigen immunoblots. Malaria-positive sera from Papua New Guinean subjects presumed to be uninfected with HIV produced a variety of bands, some of intense prominence, to HIV antigen on diagnostic Western blots. PIP: Serum samples from three populations of Papua New Guinea, where Plasmodium falciparum malaria and human T-lymphotropic virus type 1 (HTLV-1) are coendemic at high prevalence rates, showed statistically significant ELISA co-seropositivity and co-seronegativity. Cross-reactivity was further indicated by the presence of 10 bands ranging from 134 kDa to 18 kDa on immunoblots of electrophoresed whole lysate P. falciparum antigen against serum of HTLV-1 seropositive patients from an area where malaria is not present. Similarly, sera from patients positive for HIV from a nonmalarious region produced immunoblot bands ranging from 134 kDa to 33 kDa to the P. falciparum antigen. The HTLV-1 and HIV serum samples yielded a number of immunoblot bands when reacted to an electrophoresed human O type red cell membrane antigen, but those bands had no identity to the cross-reactive bands on the P. falciparum antigen immunoblots. Malaria-positive sera from Papua New Guinean subjects presumed to be uninfected with HIV produced a variety of bands, some of intense prominence, to HIV antigen on diagnostic Western blots.
Antibodies, Protozoan - immunology ; Enzyme-Linked Immunosorbent Assay ; HIV Seropositivity - immunology ; Papua New Guinea - epidemiology

Field rodents involved in ecological food chains and which are the prey of carnivores in the natural environment may serve as reservoir hosts for Toxoplasma gondii infection in humans, however, no data has been published to date in Korea. A total of 1,008 Apodemus agrarius, a dominant species of field rodents in Korea, were trapped at various locations around the country, and their serum antibody (IgG) levels to T. gondii were examined by ELISA. The mean absorbance was 0.11, and fifteen samples (1.49%) showed positive titers from 0.18 to 0.59. The seropositive samples were analyzed by immunoblot. Five of them showed reactive bands to T. gondii water soluble antigens of 30, 35, and 43 kDa. This immunoblot analysis showed very similar patterns to that obtained using sera of experimentally infected mice with T. gondii. The present study presents indirect evidence of the existence of T. gondii in field rodents in Korea.
Animal ; Antibodies, Protozoan/blood* ; Antigens, Protozoan/immunology ; Enzyme-Linked Immunosorbent Assay ; Immunoblotting ; Molecular Weight ; Muridae/parasitology* ; Seroepidemiologic Studies ; Toxoplasma/isolation & purification* ; Toxoplasma/immunology

An ELISA was established to measure bovine IgG directed against the recombinant antigenic determinant of Nc-p43, a major surface antigen of Neospora caninum. In a previous study, two thirds of the Cterminal of the molecule was expressed as a 6 x His tagged protein (Ncp43P) for ELISA using 2/3 of the N-terminal of SAG1 from Toxoplasma gondii as a control (TgSAG1A). Among 852 cattle sera collected from stock farms scattered nation-wide, 103 sera (12.1%) were found to react with Ncp43P positively, but no positive reaction was observed with TgSAG1A. This study shows that Ncp43P could be available as an efficient antigen for the diagnosis of neosporosis in cattle. Furthermore, it together with TgSAG1A, could be useful for the differential diagnosis of N. caninum and T. gondii infections in other mammals.
Animals ; Antibodies, Protozoan ; Cattle ; Cattle Diseases/diagnosis/epidemiology ; Coccidiosis/diagnosis/epidemiology/veterinary ; Enzyme-Linked Immunosorbent Assay/methods/*veterinary ; Immunoglobulin G/*analysis ; Neospora/*immunology ; Protozoan Proteins/*immunology ; Seroepidemiologic Studies

Animals ; Antibodies, Protozoan ; analysis ; Antigens, Protozoan ; analysis ; Asthma ; blood ; parasitology ; Child ; Child, Preschool ; Female ; Humans ; Infant ; Male ; Toxoplasma ; immunology ; Toxoplasmosis ; blood

The nfa1 gene was cloned from a cDNA library of pathogenic Naegleria fowleri by immunoscreening; it consisted of 360 bp and produced a 13.1 kDa recombinant protein (rNfa1) that showed the pseudopodia-specific localization by immunocytochemistry in the previous study. Based on the idea that the pseudopodia-specific Nfa1 protein mentioned above seems to be involved in the pathogenicity of N. fowleri, we observed the effect of an anti-Nfa1 antibody on the proliferation of N. fowleri trophozoites and the cytotoxicity of N. fowleri trophozoites on the target cells. The proliferation of N. fowleri trophozoites was inhibited after being treated with an anti-Nfa1 polyclonal antibody in a dose-dependent manner for 48 hrs. By a light microscope, CHO cells co-cultured with N. fowleri trophozoites (group I) for 48 hrs showed severe morphological destruction. On the contrary, CHO cells co-cultured with N. fowleri trophozoites and anti-Nfa1 polyclonal antibody (1: 100 dilution) (group II) showed less destruction. In the LDH release assay results, group I showed 50.6% cytotoxicity, and group II showed 39.3%. Consequently, addition of an anti-Nfa1 polyclonal antibody produced a decreasing effect of in vitro cytotoxicity of N. fowleri in a dosedependent manner.
Animals ; Antibodies, Protozoan/*immunology ; Antigens, Protozoan/genetics/*immunology ; CHO Cells ; Dose-Response Relationship, Immunologic ; Female ; Hamsters ; Mice ; Mice, Inbred BALB C ; Naegleria fowleri/growth & development/immunology/*pathogenicity ; Protozoan Proteins/genetics/*immunology ; Recombinant Proteins/immunology ; Support, Non-U.S. Gov't

A Cryptosporidium parvum sporozoite and oocyst lambda gt11 cDNA library was screened with a hyperimmune rabbit serum that was developed against insoluble fragments of ultrasonicated oocysts. A clone named Cp22.4.1 encoding a protein of 231 amino acids with 4 zinc-finger domains characterized by a Cys-X2-Cys-X4-His-X4-Cys motif was isolated and characterized. There was a complete match between the sequencing data of the coding region of Cp22.4.1 and the corresponding gene at chromosomal level. Cloning in a pBAD-TOPO-TA expression vector permitted to evaluate the antigenicity of the recombinant His-tagged antigen. This antigen was recognized by 2 out of 5 sera from Cryptosporidium immune calves and not by sera from parasite naive animals.
Amino Acid Sequence ; Animals ; Antibodies, Protozoan/*blood ; Antigens, Protozoan/chemistry/*immunology ; Base Sequence ; Cattle/*immunology ; Cryptosporidium parvum/*immunology ; Molecular Sequence Data ; Protozoan Proteins/chemistry/genetics ; Rabbits ; Recombinant Proteins ; Zinc Fingers/genetics/*immunology