摘要:

T cell responses to leucoagglutinin, PPD, and sevenPlasmodium falciparumblood stages antigens were investigated in 164 cord blood samples from Cameroonian neonates.In vitroT cell responses were measured by lymphocyte proliferation, and IL‐2, IFN‐γ, and IL‐4 release in the presence of crude schizont extract, purified Pf155/RESA protein, and synthetic peptides from Pf155/RESA. Following culture in presence of leucoagglutinin or PPD, proliferation and cytokine production were very low, as compared to adults from the same area. Interestingly, following stimulation of cord blood lymphocytes by malaria antigens, the percentage of responders and the mean level of positive responses were of the same order than those observed in adults for IL‐2 production, while proliferative and IL‐4 responses were only marginally decreased. Conversely, IFN‐γ production was highly reduced, as compared to adults. Our results demonstrate that prenatal immune priming to malarial antigens is common in this area and that the fetal immune system is able to respond to antigenic stimuli, as cells proliferate and generate cytokines. As cord blood lymphocytes may be induced to differentiate into effector cells producing predominantly Th1 or Th2 cytokines, malaria during pregnancy might direct the functional capacity of fetal T cells to respond to furt

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-19.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

The increase of HLA‐DR3 and complotype SCO1 previously found in Mexican mestizo adults with E. histolytica amoebic abscess of the liver, was also found in Mexican mestizo children of either sex with the same disease, when compared to the healthy control population (adults and/or children) of the same ethnic and socioeconomic background. This HLA and complotype pattern was not found in Mexican Mestizo patients with amoebic rectocolitis. No linkage disequilibrium was found between these and the other MHC determinants tested in this survey. Thus, HLA‐DR3 and SCO1 may constitute primary, independent risk factors, not for any kind of amoebic tissue invasion (i.e. amoebic rectocolitis), but specifically for amoebic liver abscess, irrespective of age or sex. The possibility of linkage disequilibrium with other factors (i.e. the TNF family) within or close to the MHC that were not tested in this study, is discussed. Children with amoebic liver abscess revealed a significant increase in HLA‐DR5, and the absence of HLA‐DR6 when compared to adults with amoebic liver abscess, suggesting that at least in this ethnic group these class II HLA traits may contribute to some of the peculiarities of pediatric amoebic liver abscess as opposed to the adult version of this disease. HLA‐DR3, SCO1, but also HLA‐DR5 and HLA‐DR6 have all been associated with certain forms of immune‐dysfunction, and may thus contribute to some of the clinical and immunological features of this pa

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-16.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

There is increasing interest in the application of serological methods to macro‐parasite infections to indicate infection intensity, which in turn is related to pathogenicity. Colic is the single most important cause of mortality in horses and there is evidence that a proportion of colic cases are associated with infection with the intestinal cestodeAnoplocephala perfoliata.In order to develop better tools to investigate this association, the correlation between antigen‐specific equine IgG and IgG(T) and infection intensity ofA. perfoliatawas investigated. Affinity purification of a 12/13 kDa protein doublet from crude excretory/secretory (E/S) products, and its use in enzume linked immunosorbent assays (ELISA) is described. Its use in the immunodiagnosis of equine cestodosis and the correlation of anti‐12/13 kDa IgG and IgG(T) with parasite burden is investigated using sera from 94 horses of known tapeworm infection intensity. The anti‐12/13 kDa IgG and IgG(T) ELISAs gave correlation coefficients with infection intensity of 0.56 and 0.63 respectively. Linear regression analysis also indicated that anti‐12/13 kDa IgG(T) was the best predictor of infection intensity. The decay of anti‐12/13 kDa IgG(T) in horses following the elimination ofA. perfoliatais demonstrated for four horses. Specificity of the anti‐12/13 kDa IgG(T) ELISA is investigated with sera from 33A. perfoliatanegative horses with other helminth infections. Immunoblotting studies demonstrate no cross‐reactivity betweenA. perfoliata12/13 kDa antigen and the protein antigens of other helminths. It is concluded that assay of anti‐12/13 kDa IgG(T) provides a useful tool for the assessment ofA perfoliatainfection intensity for clinical diagnosis

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-18.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

The protective efficacy of a recombinantTaenia ovisvaccine antigen, 45W, was compared in sheep vaccine trials with antigen expressed by the full length 45W cDNA and by incomplete copies of the cDNA. Vaccine trials were also carried out using antigen expressed by a cDNA (45S) having a sequence similar, but not identical, to 45W. Stability of the 45W antigen expressed inEscherichia coliwas found to be increased after deletion of cDNA sequence encoding 19 COOH‐terminal amino acids. This truncated form of the antigen was designated 45WB/X. Vaccination of sheep with antigen expressed by 45W, 45WB/X, as well as full length 45W and 45S cDNAs, induced high levels of protection. Vaccination with antigen expressed by an incomplete copy of the 45S cDNA clone did not induce protection. Comparison of deduced amino acid sequences for these clones suggests that the host‐protective epitope(s) of the 45W antigen occur on either or both of the 23 and 9 amino acid peptides at the amino and carboxyl termini of 45W, respectively. Antibody binding epitopes of 45W were investigated in ELISA using overlapping 9 amino acid peptides. Protection was found to correlate with the induction of antibody to two 9 amino acid pep

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-20.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

To determine amino acid sequences of the Plasmodium falciparum MSP‐1 protein that interact with red blood cell membranes in a specific receptor‐ligand interaction, 78 sequential peptides, 20 amino acids long and spanning the entire length of the molecule, were synthesized and analysed with a specific binding assay developed for this purpose. Results show that peptides based on conserved and dimorphic regions of MSP‐1, interact with human red blood cells (RBCs). This interaction occurs predominantly with peptides contained within the MSP‐1 proteolytic fragments of 83 kDa, 38 kDa, 33 kDa and 19 kDa. Affinity constants of these peptides were between 140 and 250 nM. Peptide‐RBC binding post enzyme treatment showed that the RBC receptors are not sialic acid dependent and appear to be proteic in nature. Some of these peptides inhibited merozoite invasion of RBCs yet did not inhibit intra‐erthrocytic development. These peptides, in conjunction with those from other merozoite surface proteins, may be used to rationally design a second generation of synthetic peptide

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-15.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

Naturally acquired humoral immune responses to Pfs16, an integral membrane protein expressed inPlasmodium falciparumgametocytes and sporozoites, were investigated in The Gambia. A high prevalence of antibodies to this molecule was detected by peptide ELISA. Ninety‐three per cent of the people taking part in a survey at the end of the rainy season (November) had serum antibodies to one or more synthetic peptides spanning the sequence; 88% reacted with one particular peptide sequence (IMLIILSGIVGFKVK) whereas only one out of ten non‐Gambians (taking anti‐malarial prophylaxis with no history of infection) reacted with the peptide. Epitope mapping with mouse MoAbs has shown that this peptide is located on a part of the molecule differing from immunodominant regions of the molecule identified in a previous study in Papua New G

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-17.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

Nitric oxide (NO) is implicated in a variety of major cellular functions including defence from invasion by microbical pathogens. Evidence has been presented suggesting that it is an important mediator of protection in the early non‐specific responses to malaria in mice infected with Plasmodium chabaudi(Taylor‐Robinson et al. 1993). Other data from in vitro studies on the asexual stages of human parasite Plasmodium falciparum indicated that while nitric oxide itself may not be inhibitory to parasite development, its downstream products do have some anti‐plasmodial activity (Rockett et al. 1991) and these could be generated by macrophages (Gyan et al. 1994 ). Similarly, the sexual phases of both rodent (Motard et al. 1993) and human malaria (Naotunne et al. 1993) are reportedly susceptible to the toxic effects mediated by nitric oxide generated by blood leucocytes in the course of transmission to the mosquito

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-14.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY