Publications
381 results found
FOWLER RE, SINDEN RE, PUDNEY M, 1995, INHIBITORY ACTIVITY OF THE ANTIMALARIAL ATOVAQUONE (566C80) AGAINST OOKINETES, OOCYSTS, AND SPOROZOITES OF PLASMODIUM-BERGHEI, JOURNAL OF PARASITOLOGY, Vol: 81, Pages: 452-458, ISSN: 0022-3395
- Author Web Link
- Cite
- Citations: 35
MARGOS G, KURTENBACH K, POSNETT E, et al., 1995, DEPRESSION OF THE PLASMODIUM-BERGHEI OOKINETE PROTEIN PBS21 IN A BACULOVIRUS-INSECT CELL SYSTEM PRODUCES AN EFFICIENT TRANSMISSION-BLOCKING IMMUNOGEN, PARASITE IMMUNOLOGY, Vol: 17, Pages: 167-176, ISSN: 0141-9838
- Author Web Link
- Cite
- Citations: 11
HOGH B, THOMPSON R, HETZEL C, et al., 1995, SPECIFIC AND NONSPECIFIC RESPONSES TO PLASMODIUM-FALCIPARUM BLOOD-STAGE PARASITES AND OBSERVATIONS ON THE GAMETOCYTEMIA IN SCHOOLCHILDREN LIVING IN A MALARIA-ENDEMIC AREA OF MOZAMBIQUE, AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE, Vol: 52, Pages: 50-59, ISSN: 0002-9637
- Author Web Link
- Cite
- Citations: 37
THOMPSON J, SINDEN RE, 1994, IN-SITU DETECTION OF PBS21 MESSENGER-RNA DURING SEXUAL DEVELOPMENT OF PLASMODIUM-BERGHEI, MOLECULAR AND BIOCHEMICAL PARASITOLOGY, Vol: 68, Pages: 189-196, ISSN: 0166-6851
- Author Web Link
- Cite
- Citations: 40
RANAWAKA GRR, FLECK SL, BLANCO ARA, et al., 1994, CHARACTERIZATION OF THE MODES OF ACTION OF ANTI-PBS21 MALARIA TRANSMISSION-BLOCKING IMMUNITY - OOKINETE TO OOCYST DIFFERENTIATION IN-VIVO, PARASITOLOGY, Vol: 109, Pages: 403-411, ISSN: 0031-1820
- Author Web Link
- Cite
- Citations: 32
Ranawaka GR, Fleck SL, Blanco AR, et al., 1994, Characterization of the modes of action of anti-Pbs21 malaria transmission-blocking immunity: ookinete to oocyst differentiation in vivo., Parasitology, Vol: 109 ( Pt 4), Pages: 403-411, ISSN: 0031-1820
The impact of immune sera, and peripheral blood cells (PBC) from mice immunized with Plasmodium berghei ookinetes; and of purified immunoglobulin or Fab fragments from anti-Pbs21 monoclonal antibody 13.1, upon establishment of oocyst infections in the mosquito was studied. Infections were initiated either from gametocyte-infected mice, or membrane feeders which contained either gametocytes or mature ookinetes. PBC from ookinete-immunized mice presented with non-immune serum failed to show any transmission-blocking activity. Anti-ookinete serum, intact anti-Pbs21 monoclonal antibody 13.1 or its Fab fragments, all inhibited oocyst formation significantly. When gametocyte-infected mice or gametocytes in membrane feeds were used, inhibition did not directly correlate with antibody concentration. In membrane feeders that contained ookinetes and antibody, concentration-dependent inhibition usually occurred. The efficacy of purified 13.1 IgG was dependent upon the ookinete concentration. The ookinete plasmalemma and cytoplasm were significantly disturbed after 12 h in bloodmeals that contained antibody 13.1, but not in the isotype controls. These changes may have caused the observed failure of the ookinete to migrate as rapidly as the controls from the destructive environment of the bloodmeal.
BILLINGSLEY PF, MEDLEY GF, CHARLWOOD D, et al., 1994, RELATIONSHIP BETWEEN PREVALENCE AND INTENSITY OF PLASMODIUM-FALCIPARUM INFECTION IN NATURAL-POPULATIONS OF ANOPHELES MOSQUITOS, AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE, Vol: 51, Pages: 260-270, ISSN: 0002-9637
- Author Web Link
- Cite
- Citations: 52
JONES IW, DENHOLM AA, LEY SV, et al., 1994, SEXUAL DEVELOPMENT OF MALARIA PARASITES IS INHIBITED IN-VITRO BY THE NEEM EXTRACT AZADIRACHTIN, AND ITS SEMISYNTHETIC ANALOGS, FEMS MICROBIOLOGY LETTERS, Vol: 120, Pages: 267-273, ISSN: 0378-1097
- Author Web Link
- Cite
- Citations: 65
Ranawaka GR, Alejo-Blanco AR, Sinden RE, 1994, Characterization of the effector mechanisms of a transmission-blocking antibody upon differentiation of Plasmodium berghei gametocytes into ookinetes in vitro., Parasitology, Vol: 109 ( Pt 1), Pages: 11-17, ISSN: 0031-1820
The transmission-blocking monoclonal antibody 13.1, which recognizes the ookinete surface antigen Pbs21 of Plasmodium berghei, and an IgG2a isotype control antibody 26.37 were purified by caprylic acid and ammonium sulphate precipitation. Fab fragments were prepared by papain digestion. IgG but not Fab from antibody 13.1 reduced ookinete formation by P. berghei in culture by as much as 94% at a concentration of 100 micrograms/ml. There was little difference in antibody efficacy in the range 6.25-400 micrograms/ml in this assay. The parasite was most sensitive to antibody activity in the first 6-9 h of culture, i.e. the gamete/zygote and early retort stages. Peripheral blood leucocytes (PBL) were essential to achieve maximal inhibition by mAb 13.1 (activity was abrogated totally if PBL were removed). Together the data suggest that one of the mechanisms of action of this antibody is antibody-mediated PBL killing. Phagocytosis of parasites was noted in these experiments in all cultures. We have not attempted in this study to distinguish between Fc-mediated opsonization, as opposed to antibody-dependent cellular cytotoxicity.
RANAWAKA GRR, ALEJOBLANCO AR, SINDEN RE, 1994, CHARACTERIZATION OF THE EFFECTOR MECHANISMS OF A TRANSMISSION-BLOCKING ANTIBODY UPON DIFFERENTIATION OF PLASMODIUM-BERGHEI GAMETOCYTES INTO OOKINETES IN-VITRO, PARASITOLOGY, Vol: 109, Pages: 11-17, ISSN: 0031-1820
- Author Web Link
- Cite
- Citations: 26
KUMAR S, VANPELT JF, ODOWD CA, et al., 1994, EFFECTS OF HORMONES AND CYSTEINE PROTEASE MODULATORS ON INFECTION OF HEPG2 CELLS BY PLASMODIUM-BERGHEI SPOROZOITES IN-VITRO DETERMINED BY ELISA IMMUNOASSAY, JOURNAL OF PARASITOLOGY, Vol: 80, Pages: 414-420, ISSN: 0022-3395
- Author Web Link
- Cite
- Citations: 3
Fowler RE, Billingsley PF, Pudney M, et al., 1994, Inhibitory action of the anti-malarial compound atovaquone (566C80) against Plasmodium berghei ANKA in the mosquito, Anopheles stephensi., Parasitology, Vol: 108 ( Pt 4), Pages: 383-388, ISSN: 0031-1820
The activity of atovaquone against Plasmodium berghei ANKA during sporogonic development has been examined. Anopheles stephensi mosquitoes were fed on gametocyte infected mice which had been treated 8 h previously with atovaquone or diluent alone. Mosquito midguts were examined for oocysts, and salivary gland infections were estimated using an ELISA for the circumsporozoite protein (CSP). The number of oocysts per midgut fell by at least 97% when mosquitoes were fed on mice dosed with 0.1-10 mg atovaquone/kg body weight. This was paralleled by a decrease in the prevalence of oocyst-infected mosquitoes from 70-90% in controls to 40% or 10% respectively. No oocysts were observed at a dose of 100 mg/kg. CSP ELISA results indicated that mosquitoes fed on atovaquone failed to produce sporozoites. Mosquitoes which fed on gametocytaemic, atovaquone-treated mice (0.1-100 mg/kg) did not transmit malaria to naive mice. These results demonstrate that atovaquone has a highly potent inhibitory activity against the mosquito stages of P. berghei.
FOWLER RE, BILLINGSLEY PF, PUDNEY M, et al., 1994, INHIBITOR ACTION OF THE ANTIMALARIAL COMPOUND ATOVAQUONE (566C80) AGAINST PLASMODIUM-BERGHEI ANKA IN THE MOSQUITO, ANOPHELES-STEPHENSI, PARASITOLOGY, Vol: 108, Pages: 383-388, ISSN: 0031-1820
- Author Web Link
- Cite
- Citations: 21
FLECK SL, BUTCHER GA, SINDEN RE, 1994, PLASMODIUM-BERGHEI - SERUM-MEDIATED INHIBITION OF INFECTIVITY OF INFECTED MICE TO ANOPHELES-STEPHENSI MOSQUITOS, EXPERIMENTAL PARASITOLOGY, Vol: 78, Pages: 20-27, ISSN: 0014-4894
- Author Web Link
- Cite
- Citations: 11
MATSUOKA H, PATON MG, BARKER GC, et al., 1994, STUDIES ON THE IMMUNOGENICITY OF A RECOMBINANT OOKINETE SURFACE-ANTIGEN PBS21 FROM PLASMODIUM-BERGHEI EXPRESSED IN ESCHERICHIA-COLI, PARASITE IMMUNOLOGY, Vol: 16, Pages: 27-34, ISSN: 0141-9838
- Author Web Link
- Cite
- Citations: 6
JANSE CJ, PONZI M, SINDEN RE, et al., 1994, CHROMOSOMES AND SEXUAL DEVELOPMENT OF RODENT MALARIA PARASITES, CEC/Latin-American Malaria Conference/IV CEC Makarua Contract Holders Meeting, Publisher: MEM INST OSWALDO CRUZ, Pages: 43-46, ISSN: 0074-0276
- Author Web Link
- Cite
- Citations: 2
Barker GC, RodrÃguez MH, Sinden RE, 1994, Attempted isolation of the gene encoding the 21 Kd Plasmodium berghei ookinete transmission blocking antigen from Plasmodium yoelli and Plasmodium vivax., Mem Inst Oswaldo Cruz, Vol: 89 Suppl 2, Pages: 37-41, ISSN: 0074-0276
The 21kD ookinete antigen of Plasmodium berghei (Pbs 21) has been shown to elicit an effective and long lasting transmission blocking immune response in mice. Having cloned and sequenced this antigen (Paton et al. 1993) the sequence was compared to the genes of the same family previously identified in P. falciparum, P. gallinaceum (Kaslow et al. 1989) and P. reichenowi (Lal et al. 1990). Four conserved areas were identified in this comparison, to which degenerate oligonucleotides were designed. PCR amplification and screening of genomic libraries was then carried out using these oligonucleotides. The P. yoelii gene was successfully cloned and a number of novel P. vivax genes identified but the P. vivax homologue of Pbs21 remains elusive.
KOBAYASHI J, MATSUOKA H, CHINZEI Y, et al., 1994, PRODUCTION OF A TRANSMISSION BLOCKING VACCINE CANDIDATE OF RODENT MALARIA PLASMODIUM-BERGHEI USING A BACULOVIRUS EXPRESSION VECTOR SYSTEM, 6th International Meeting of the Japanese-Association-for-Animal-Cell-Technology; Animal Cell Technology - Basic and Applied Aspects, Publisher: KLUWER ACADEMIC PUBL, Pages: 41-45
Janse CJ, Ponzi M, Sinden RE, et al., 1994, Chromosomes and sexual development of rodent malaria parasites., Mem Inst Oswaldo Cruz, Vol: 89 Suppl 2, Pages: 43-46, ISSN: 0074-0276
BARKER GC, RODRIGUEZ MH, SINDEN RE, 1994, ATTEMPTED ISOLATION OF THE GENE ENCODING THE 21-KD PLASMODIUM-BERGHEI OOKINETE TRANSMISSION-BLOCKING ANTIGEN FROM PLASMODIUM-YOELLI AND PLASMODIUM-VIVAX, CEC/Latin-American Malaria Conference/IV CEC Makarua Contract Holders Meeting, Publisher: MEM INST OSWALDO CRUZ, Pages: 37-41, ISSN: 0074-0276
- Author Web Link
- Cite
- Citations: 1
CRAMPTON JM, GALLER R, SINDEN RE, et al., 1993, THE GENETIC WAR AGAINST MOSQUITOS, RECHERCHE, Vol: 24, Pages: 1218-1227, ISSN: 0029-5671
- Author Web Link
- Cite
- Citations: 7
RANAWAKA G, ALEJOBLANCO R, SINDEN RE, 1993, THE EFFECT OF TRANSMISSION-BLOCKING ANTIBODY INGESTED IN PRIMARY AND SECONDARY BLOODFEEDS, UPON THE DEVELOPMENT OF PLASMODIUM-BERGHEI IN THE MOSQUITO VECTOR, PARASITOLOGY, Vol: 107, Pages: 225-231, ISSN: 0031-1820
- Author Web Link
- Cite
- Citations: 27
BUTCHER GA, COUCHMAN AF, VANPELT JF, et al., 1993, THE SCID MOUSE AS A LABORATORY MODEL FOR DEVELOPMENT OF THE EXOERYTHROCYTIC STAGES OF HUMAN AND RODENT MALARIA, EXPERIMENTAL PARASITOLOGY, Vol: 77, Pages: 257-260, ISSN: 0014-4894
- Author Web Link
- Cite
- Citations: 9
Ranawaka G, Alejo-Blanco R, Sinden RE, 1993, The effect of transmission-blocking antibody ingested in primary and secondary bloodfeeds, upon the development of Plasmodium berghei in the mosquito vector., Parasitology, Vol: 107 ( Pt 3), Pages: 225-231, ISSN: 0031-1820
The effects of purified monoclonal immunoglobulins from control, or transmission-blocking anti-Pbs21 antibodies, upon the infection of Anopheles stephensi by ookinetes of Plasmodium berghei are compared. Anti-Pbs21 antibody reduced mean intensity and prevalence of infection by 94.7 and 58.7% respectively if added to the infectious bloodfeed at a concentration of 100 micrograms/ml. Fab fragments were of similar efficacy. No transmission enhancement was detected with declining antibody concentrations. Addition to subsequent (second) feeds reduced mean oocyst intensity but not prevalence. The reduction in blockade declined from 41% at day 2, to 4% at day 8. Second bloodfeeds, containing control globulin taken 4 or 6 days (but not 2 days) after infection, increased sporozoite burden in the salivary glands. At all times anti-Pbs21 reduced sporozoite number in the thorax compared to time-matched controls, but again highest gland intensities were obtained when the second bloodfeed was given on day 4. We conclude that second bloodfeeds containing transmission-blocking antibody simultaneously serve two opposing roles, (1) inhibition of parasite development and (2) the supply of nutrients which permit more sporozoites to be produced by each oocyst.
Sinden RE, Barker GC, Paton MJ, et al., 1993, Factors regulating natural transmission of Plasmodium berghei to the mosquito vector, and the cloning of a transmission-blocking immunogen., Parassitologia, Vol: 35 Suppl, Pages: 107-112, ISSN: 0048-2951
Naturally occurring factors that regulate the infectivity of P. berghei infected rodent hosts to the mosquito vector in vivo have been compared in T.O., Balb/C and immunodeficient SCID mice. No detectable differences in infectivity were observed suggesting B and T cell mediated factors are not involved. Further studies investigated roles for macrophage colony stimulating factors, the cytokines IFN gamma and TNF alpha, of neutrophils, and of nitric oxide in the SCID mouse, but have failed to demonstrate an important role in vivo for any factor examined. Differences between these results and those obtained in vitro on the human and primate parasites must therefore be explained by biological differences between the parasite/host combinations, or by technical differences in experimental designs. Induced immunity to the ookinete surface antigen Pbs 21 of P. berghei can totally block the transmission of the parasite from the gametocyte infected host to the vector. We have cloned the gene encoding Pbs 21 and shown it bears striking structural similarities to Pfs 25, Pgs 25 and more particularly Pgs 28 in that it has a high cysteine content (9.5%), 4 EGF-like domains and hydrophobic amino-'signal'--and carboxyl-'anchor' sequences. The encoding gene is on chromosome 5 and is found also in P. chabaudi, P. yoelii and P. vinckei.
MULLER HM, CRAMPTON JM, DELLATORRE A, et al., 1993, MEMBERS OF A TRYPSIN GENE FAMILY IN ANOPHELES-GAMBIAE ARE INDUCED IN THE GUT BY BLOOD MEAL, EMBO JOURNAL, Vol: 12, Pages: 2891-2900, ISSN: 0261-4189
- Author Web Link
- Cite
- Citations: 149
Medley GF, Sinden RE, Fleck S, et al., 1993, Heterogeneity in patterns of malarial oocyst infections in the mosquito vector., Parasitology, Vol: 106 ( Pt 5), Pages: 441-449, ISSN: 0031-1820
Oocyst prevalence and intensity have been recorded in 349 laboratory infections of Anopheles stephensi with Plasmodium berghei. Intensity and prevalence of infection are shown to be predictably related. The structure and heterogeneity in the infections has been analysed with the objective of describing the biological mechanisms by which the observed negative binomial oocyst distributions are generated. The analysis has revealed that the most likely processes lie within the population dynamic events of malaria within the mosquito, namely gametogenesis, fertilization and mortality. The distribution is similar in all Plasmodium-mosquito combinations examined so far, whether they are of laboratory (P. gallinaceum in Aedes aegypti) or field (P. vivax in An. albimanus and P. falciparum in An. gambiae s.l. and An. funestus) origin. Further we conclude that there is competition between parasites in the vector. Oocyst frequency distribution analysis shows that under natural conditions of transmission intensity, and even under the best laboratory conditions, significant numbers (> 10%) of fully susceptible mosquitoes will not be infected under conditions where the mean infection is as high as 250 oocysts. Failure to infect is not therefore an absolute indicator of refractoriness. In assessing transmission data it is shown that sample sizes should not be less than 50, and ideally 100 mosquitoes, if reliable data are to be obtained. In field it is suggested that difficulties in determining the low natural intensity of oocyst infections indicate that prevalence estimates are a useful and accessible parameter to measure.(ABSTRACT TRUNCATED AT 250 WORDS)
MEDLEY GF, SINDEN RE, FLECK S, et al., 1993, HETEROGENEITY IN PATTERNS OF MALARIAL OOCYST INFECTIONS IN THE MOSQUITO VECTOR, PARASITOLOGY, Vol: 106, Pages: 441-449, ISSN: 0031-1820
- Author Web Link
- Cite
- Citations: 100
PATON MG, BARKER GC, MATSUOKA H, et al., 1993, STRUCTURE AND EXPRESSION OF A POSTTRANSCRIPTIONALLY REGULATED MALARIA GENE ENCODING A SURFACE PROTEIN FROM THE SEXUAL STAGES OF PLASMODIUM-BERGHEI, MOLECULAR AND BIOCHEMICAL PARASITOLOGY, Vol: 59, Pages: 263-275, ISSN: 0166-6851
- Author Web Link
- Cite
- Citations: 147
Hollingdale MR, Sinden RE, van Pelt J, 1993, Sporozoite invasion., Nature, Vol: 362, ISSN: 0028-0836
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.