摘要:

Antibodies against sterigmatocystin (St)‐hemiacetal (HA) conjugated to bovine serum albumin (BSA) by reductive alkylation were shown to cross‐react with St‐DNA adducts in a competitive indirect ELISA. The amounts of various ligands causing 50% inhibition in binding of the antibodies with the solid phase St‐HA‐keyhole limpet hemocyanin (KLH) by St, St‐guanine (St‐Guan) and St‐formamidopyrimidine (St‐FAPy) were 0.4, 10 and 17 picomoles/assay respectively. The cross‐reactivity of the antibodies with St adducts on the single‐stranded (ss) DNA and double‐stranded (ds) DNA was also compared. The amounts causing 50% inhibition in binding of the antibodies with the solid phase St by St‐Guan‐DNA (ss), St‐Guan‐DNA (ds) and St‐FAPy‐DNA (ds) were 32, 480 and 400 picomoles per assay respectively. Enzymatically hydrolyzed St‐Guan‐DNA and St‐Guan have the same cross‐reactivity with St‐HA‐BSA antibodies. The antibodies did not interact with non‐adducted DNA at concentrations up to 2 mg ml‐1. The ELISA sensitivity for St‐Guan increased 40‐ to 100‐fold when an avidin‐biotin complex was incorporated into the system.

ISSN:0954-0105    

DOI:10.1080/09540109309354778

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This paper highlights some of the difficulties encountered in the production and characterization of beta‐type anti‐idiotype antibodies to haptenic molecules. It describes the techniques employed to overcome these problems and illustrates the importance of the screening assay format in selecting the desired antibodies. The anti‐idiotype antibodies produced were used in a variety of assay formats, some innovative, for the quantification of the pesticides paraquat and phenoxybenzoic acid (PBA). The most sensitive of these assays detected 100 pm ml‐1paraquat and 100 ng ml‐1PBA respectively. The application of these antibodies to multi‐residue tests which overcome the narrow specificity conferred by conventional immunoassay techniques is discussed.

ISSN:0954-0105    

DOI:10.1080/09540109309354779

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

We studied the therapeutic effect ofLactobacillus caseiduring an infection withSalmonella typhimuriumand the influence of the administration ofL. caseion the levels of secretory immunoglobulin A (S‐IgA) specific for the pathogen. Swiss albino mice were infected with S.typhimurium,different doses ofL. caseibeing orally administered to the animals 48 h after infection. Results showed that the dose ofL. caseiused for therapeutic purposes was extremely important, since the only partially effective one was that used for 3 consecutive days (3.6 ×109CFUs) producing an S‐IgA level slightly higher than that of the controls. Larger doses and longer feeding periods (4, 5 and 7 consecutive days) failed to improve the therapeutic effect and proved unable to check the infection. When a repeated stimulation withL. caseiwas effected in those animals that had undergone the 3‐day treatment, an enhancement in the S‐IgA levels was obtained and their survival time increased to 35 days as against 20 days for the controls without treatment. The stimulation of S‐IgA synthesis lasted only a short time after the administration of the optimum protective dose ofL. casei.Although the IgA levels obtained on the 3rd and 5th days after feeding were high in relation to those of the controls, they were not sufficient to prevent colonization. It seems likely thatL. caseistimulated the T‐ and/or B‐cells, enhancing the number of B cells that enter the IgA cycle and thus increasing the synthesis of immunoglobulin A. This stimulation is apparently closely related to theL. caseidose.

ISSN:0954-0105    

DOI:10.1080/09540109309354780

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The effect of previous oral administration ofLactobacillus caseiused as immunomodulator on the inhibition of a fibrosarcoma (a non‐intestinal tumour) was studied. BALB/c mice were fed with different doses ofL. casei(2.4, 6 and 8.4 ×109bacteria). At the end of each treatment, 5 ×105tumour cells from a methylcholanthrene‐induced fibrosarcoma were subcutaneously inoculated, tumour progression being studied for 35 days. Results showed that feeding with a 2.4 ×109dose ofL. caseibefore inoculation of the tumour cells caused a 41% suppression in tumour growth. In the case of those animals fed with the same dose in which there was no inhibition of tumour growth, an increase of 55 days in survival time was observed as against a control survival period of only 35 days. The other doses assayed proved unable to check tumour growth; on the contrary, they favoured it.

ISSN:0954-0105    

DOI:10.1080/09540109309354781

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The influence of recombinant bovine interleukin‐2 (rBoIL‐2) on mammary gland mononuclear cell proliferation in the presence of lactoferrin and serum albumin was evaluated. Mammary mononuclear cells were isolated from five pregnant Holstein cows during the periparturient period and cultured with 0, 2.5 or 25 ng ml‐1of rBoIL‐2. Lactoferrin and serum albumin were evaluated at concentrations ranging from 0 to 2.5 mg ml‐1. Both 2.5 and 25 ng ml‐1of rBoIL‐2 significantly increased mononuclear cell proliferation. Increasing concentrations of lactoferrin resulted in a dose‐dependent reduction of mononuclear cell proliferation in the presence and absence of rBoIL‐2. However, in cells from four of the five cows, rBoIL‐2 treatment (2.5 and 25 ng ml‐1) resulted in significantly enhanced mononuclear cell proliferation compared to controls (no rBoIL‐2) even in the presence of the highest concentration of lactoferrin. Serum albumin had little influence on mononuclear cell proliferation. Results of this study suggest that lactoferrin inhibits mammary gland mononuclear cell proliferation, and that rBoIL‐2 can overcome lactoferrin‐induced hyporesponsiveness.

ISSN:0954-0105    

DOI:10.1080/09540109309354782

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

An enzyme‐linked immunosorbent assay (ELISA) for the detection of porcine pepsin in milk‐clotting enzyme preparations has been developed. The assay is capable of detecting porcine pepsin in the range 1μgto 1 mg ml‐1without enhancement or modification. The specificity of the technique was studied by inhibition assay. Slight cross‐reactions with bovine rennet andMucor mieheirennet occurred at high concentrations (1.0 mg ml‐1). The ELISA used in this investigation appears to provide a quick, sensitive and specific method for the detection of porcine pepsin and has potential applications in the dairy industry.

ISSN:0954-0105    

DOI:10.1080/09540109309354783

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0954-0105    

DOI:10.1080/09540109309354777

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor