Purification of murine IgG monoclonal antibodies from ascitic fluid by precipitation with caprylic acid was compared to that: 1) by sequential precipitation with caprylic acid and (NH4)2SO4; 2) by ...affinity chromatography on either antiidiotypic monoclonal antibodies or antimouse IgG xenoantibodies; and 3) by sequential (NH4)2SO4 precipitation, ion exchange chromatography and high pressure liquid chromatography (referred to as HPLC). In terms of yield of antibodies, precipitation with caprylic acid is comparable to sequential precipitation with caprylic acid and (NH4)2SO4, but superior to affinity chromatography on antibodies and to HPLC. In terms of purity of antibodies, precipitation with caprylic acid is less efficient than the other three methods. It should also be noted that precipitation with caprylic acid is associated with a reduction in the affinity of some antibodies and is not suitable to purify murine IgA and IgG3.
BALB/c mice were immunized with the murine antihuman high-molecular-weight melanoma-associated antigen monoclonal antibodies (MoAbs) 149.53, 225.28, 653.25, and 763.74. Antiidiotypic antibodies could ...be detected in bleedings obtained 3 days following the first booster, increased in titer in bleedings obtained following the second booster, and persisted at high level in bleedings obtained 38 days following the second booster. Cross-blocking studies with a panel of anti-melanoma-associated antigen, anti-HLA Class I, and anti-HLA Class II monoclonal antibodies showed that the antisera recognize private idiotypes. The latter are located within the antigen combining site, since antiidiotypic antisera specifically inhibited the binding of the corresponding immunizing anti-human high-molecular-weight melanoma-associated antigen monoclonal antibody to cultured human melanoma cells Colo 38 in a dose-dependent fashion. The spectrotype of the anti-MoAb 149.53 antiserum comprises eight major components in the range of pH 6.2 to 7.0; those of the anti-MoAb 225.28 antiserum and of the anti-MoAb 653.25 antiserum, two major components in the ranges of pH 6.4 to 6.6 and 6.5 to 6.7, respectively; and that of the anti-MoAb 763.74 antiserum, three major components in the range of pH 6.2 to 6.4.
POEMS (Crow-Fukase) syndrome is a rare plasma cell lymphoproliferative disorder associated with polyneuropathy (P), organomegaly (O), endocrinopathy (E), monoclonal (M) gammopathy and skin (S) ...abnormalities. The latter are usually not specific and include hyperpigmentation, hypertrichosis, cutaneous angioma and skin-thickening. A 45-year-old Italian woman was admitted to hospital because of muscle weakness, marked fatigue and paresthesia of the upper and lower extremities. Two and a half years earlier, a POEMS syndrome had been diagnosed on the basis of a history of organomegaly and mild lymphadenopathy, IgA-lambda monoclonal gammopathy, hypothyroidism, severe lower and upper limb sensory-motor peripheral neuropathy and a single osteosclerotic lesion in the left humerus. Eight weeks later, she developed skin lesions bioptically shown to be due to calciphylaxis-induced cutaneous vasculitis. To our knowledge, this is the first case of POEMS syndrome with this peculiar type of vasculitis. The absence of predisposing conditions, namely renal failure, hyperparathyroidism or clotting disorders renders the pathogenetic mechanism(s) of this severe type of vasculitis more intriguing.
Of 1019 hybridomas generated from a BALB/c mouse immunized with the syngeneic anti-CD4 monoclonal antibody HP2/6, 3 were found to secrete anti-idiotypic antibodies. Detailed analysis of ...anti-idiotypic monoclonal antibodies F16-10F6, F16-14D6 and F16-16D7 showed they recognize idiotope(s) not expressed by any of the anti-CD4 monoclonal antibodies tested, including those which inhibit the binding of HP2/6 to CD4 antigen. The idiotope recognized by the three anti-idiotypic antibodies are within (or closely related to) the antigen combining site of the immunizing antibody and distinct and spatially distant from the idiotope defined by monoclonal antibody F11-2302 which was previously shown to be outside the antigen combining site of HP2/6. Although F16-14D6 and F16-16D7 are indistinguishable in isotype, binding titer to idiotopes, fine specificity on a panel of monoclonal antibodies, relation to the combining site and competitive binding, it is likely that they are structurally different and recognize two distinct combining site-related idiotopes on HP2/6, as they display different spectrotypes and induce anti-anti-idiotypic (Ab3) immune sera with different specificities. Analysis of the fine specificity of the two Ab3 immune sera suggest they share idiotopes with HP2/6 and contain antibodies reacting with CD4 antigen. Among the latter, those induced with F16-14D6 display a different CD4 epitope specificity than HP2/6. Hence, anti-idiotypic antibodies F16-14D6 and F16-16D7 behave as "network antigen" for human CD4; idiotope-triggered antibody cascade may have a role in changing the specificities of antibody.
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