摘要:

SUMMARYThe effect of Toxocara (T.) canis antigen (TcAg) on lymphocytes was studied in vitro using normal murine spleen cells and human peripheral blood lymphocytes. TcAg prepared from adult worms stimulated murine spleen cells to proliferate at concentrations of 1–125 μg/ ml. The responder cells for TcAg are B cells, because the response was depleted by the treatment of spleen cells with anti‐immunoglobulin (Ig) antibody and complement and after separation on a nylon wool column. This response was not due to the contamination of lipopolysaccharide (LPS), because TcAg could stimulate C3 HI He J spleen cells which are low responders to LPS. Not only the proliferative response but also polyclonal IgG and IgE production were stimulated with TcAg. TcAg also stimulated macrophages to produce interleukin‐1 and could stimulate human B cells. These results suggest that TcAg is a potent B cell mitogen and this activity may be relevant to the alteration of immunological functions in hosts infected with T.

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1995.tb01006.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SUMMARYMeasurement of anti‐larval responses in filaria‐exposed populations may shed light on the natural history of exposure to Wuchereria bancrofti. Using serum samples obtained by a cross‐sectional survey of 172 individuals from two neighbourhoods in Leogane, Haiti, antibody responses directed against infective stage filarial larvae (L3) were assayed by enzyme‐linked immunosorbent assay (ELISA), immunofluorescence (IFA), and immunoblot for the presence of anti‐larval antibodies. ELISA results indicated that virtually all members of both neighbourhoods mounted an anti‐larval antibody response within the first five years of life, suggesting that exposure to infection is universal. In a multiple linear regression analysis that modelled antibody levels as a function of age, gender, microfilaria status, and neighbourhood (as a proxy for transmission intensity), isotype‐specific antibody levels were found to be significantly influenced by both age and neighbourhood. Antibodies directed against the surface of L3also were age‐dependent; the prevalence of IgG antibodies detected by IF A was significantly higher in children than in adults. The prevalence of antibody recognition of 16–7 and 72–3kDa L3antigens on immunoblots was significantly greater for serum samples from microfilaraemic than amicrofilaraemic persons. These results suggest that antibody responses to larval antigens are influenced to varying degrees by age, transmission intensity, and mi

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1995.tb01007.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SUMMARYWe have investigated specific immune responses in BALB/c mice with experimentally induced secondary hydatidosis. Following intraperitoneal inoculation of brood capsules containing Echinococcus granulosus‐protoscoleces, the course of the infection was followed for 513 days. The sera of the mice were screened for the presence of a number of cytokines, and for specific antibodies. During the first 129 days of infection, high levels of cytokines TNFα, IL‐α, IFNγ, IL‐6, andIL‐10 and specific IgGl andIgG3 isotypes were detected, as compared to uninfected controls. The levels oflgM and IgG2a were slightly increased following infection, and remained elevated throughout the period of observation. The levels of IL‐lα and specific immunoglobulin of all isotypes except IgM and IgG2α, were significantly decreased 103 days post infection fp.i.), whereas TNFα was sharply decreased 129 days p.i. During the period of 129 to 209 days of infection there was an increase in secreted IL‐10, and a slow decrease in the levels of IL‐6 andlFN‐γ. Levels of IgM, IgG, IgGl, and IgG2a plateaud during this period, whereas IgG3 and TNFα showed a peak at day 190 p.i. These data suggest the induction of Th2 antibody‐mediated immunity with a parallel expansion of Thl‐mediated inflammatory responses as important mechanism of host defe

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1995.tb01008.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SUMMARYMice and rabbits immunized with recombinant forms of malaria vaccine candidate antigens rhoptry‐associated proteins 1 and 2 (RAP‐1, RAP‐2 and rRAP‐l, rRAP‐2) produce antibodies at litres equivalent to monoclonal antibody ascites fluid raised against the native proteins. Sera from animals immunized with rRAP‐l contain antibodies which recognize the native protein by indirect immunofluorescence and immunoblotting, partially inhibit erythrocyte invasion in vitro and are long lasting. Epitope mapping shows these antibodies predominantly recognize epitopes in the N‐terminal third of rRAP‐l, some of which coincide with the targets of inhibitory monoclonal antibodies. By contrast, sera from animals immunized with rRAP‐2 contain antibodies which recognize the recombinant but not

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1995.tb01009.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SUMMARYFollowing infection with Ostertagia circumcincta there was considerable variation in worm burdens, worm size and number of inhibited larvae even among sheep matched for age, sex, breed, farm of origin and history of parasite exposure. There was also substantial variation among sheep in the concentration of mast cells, globule leucocytes, eosinophils, IgA‐positive plasma cells and parasite‐specific IgA in the abomasal mucosa. With the exception of faecal egg counts over time, the parasitological and immunological traits were all continually distributed among animals and sheep did not fall into discrete high and low‐responder categories. The responses were correlated. Sheep with more mast cells also had more globule leucocytes, more eosinophils, more IgA plasma cells and greater amounts of parasite‐specific IgA in the abomasal mucosa. Female worm length was strongly and positively correlated with the number of eggs in utero. Faecal egg counts were associated with variation in worm number and with variation in the number of eggs in utero. The worm burden was negatively correlated with the number of globule leucocytes in the abomasal mucosa, suggesting that worm numbers are regulated by immediate hypersensitivity reactions. Decreased female worm length was associated with an increased local IgA response to fourth stage larvae. The number of inhibited larvae was positively associated with the size of the local IgA response and positively associated with the size of the worm burden. The results suggest that variation among mature sheep in faecal egg counts is due, at least in part, to variation in local IgA responses which regulate worm fecundity and to variation in local immediate hypersensitivity reactions which regulate worm

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1995.tb01010.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

SUMMARYImmunity to Onchocerca microfilariae (mf) in mice is associated with CD4+Th2 cells and is dependent on IL‐5. In view of the role ofIL‐4 in the development of Th2 cells, we have utilized IL‐4 gene knockout mice (IL‐4‐1‐) to investigate microfilarial clearance and resistance to reinfection. Paradoxically, in the absence of IL‐4 there is accelerated clearance of microfilariae during a primary infection and unimpeded expression of resistance to reinfection. IL‐4‐1‐mice showed a lack of an IgE response although peripheral eosinophilia was equivalent to wildtype controls. The data presented here suggest that elimination ofmfcan occur independent of IL‐4 and that in this model it may even be de

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1995.tb01011.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY