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Allergen immunotherapy (IT) has long-term efficacy in IgE-mediated allergic rhinitis and asthma. IT has been shown to modify lymphocyte responses to allergen, inducing IL-10 production and IgG Abs. In contrast, a putative role for IgA and local TGF-beta-producing cells remains to be determined. In 44 patients with seasonal rhinitis/asthma, serum IgA1, IgA2, and polymeric (J chain-containing) Abs to the major allergen Phl p 5 were determined by ELISA before and after a 2-year double-blind trial of grass pollen (Phleum pratense) injection IT. Nasal TGF-beta expression was assessed by in situ hybridization. Sera from five IT patients were fractionated for functional analysis of the effects of IgA and IgG Abs on IL-10 production by blood monocytes and allergen-IgE binding to B cells. Serum Phl p 5-specific IgA2 Abs increased after a 2-year treatment (approximately 8-fold increase, p = 0.002) in contrast to IgA1. Increases in polymeric Abs to Phl p 5 (approximately 2-fold increase, p = 0.02) and in nasal TGF-beta mRNA (p = 0.05) were also observed, and TGF-beta mRNA correlated with serum Phl p 5 IgA2 (r = 0.61, p = 0.009). Post-IT IgA fractions triggered IL-10 secretion by monocytes while not inhibiting allergen-IgE binding to B cells as observed with IgG fractions. This study shows for the first time that the IgA response to IT is selective for IgA2, correlates with increased local TGF-beta expression, and induces monocyte IL-10 expression, suggesting that IgA Abs could thereby contribute to the tolerance developed in IT-treated allergic patients.

The base degradation of (L Co(pi-(3)-1,2-B9C2H11))(z) followed by oxidation has been found to effect a polyhedral contraction to give (L Co(pi-(1) -2,4-B8C2H10))(z); where L=C5H5(-) and z=O or L=(3)-1,2-B9C2H11(2-) and z=-1. Further degradation of these complexes using FeCl3 in ethanol gave ((pi-C5H5) Co(pi-B7C2H11)) and ((pi-(3)-1,2-B9C2H11)Co(pi-B7C2H9)). The former complex eliminates hydrogen at 150C to give ((pi-C5H5)Co(pi-(2)-1,10-B7C2H9)).

Reaction of the bis-pi-dicarbollide ligand complexes of Co(+3) and Fe(+3) with CS2 in the presence of AlCl3 and HCl produced the firts examples of zwitterionic species having an -S-CH(+)-S- bridge between boron atoms of the two dicarbollide ion ligands of the complex. Similarly, a suspected -OC(CH3)(+)O- bridged species results from the reaction of acetic acid/acetic anhydride with an HClO4 catalyst. Further transformations of these species are described. (Author)

The complex (B9C2H11-Co-B8C2H10-Co-B8C2H10-Co-B9C2H11(-3)) has been prepared and its crystallographic characterization is discussed. (Author), Prepared in cooperation with Harvard Univ., Cambridge, Mass. Dept. of Chemistry. Grant NSF-GP-8077.

The base degradation followed by oxidation, of ((pi-C5H5)Co(pi-(3)-1,2-B9C2H11)) and ((pi-(3)-1,2-B9C2H11)2Co)(-) has been found to effect a polyhedral contraction to give ((pi-C5H5)Co(pi-(1)-2,4-B8C2H10)) and ((pi-(3)-1,2-B9C2H11)Co(pi-(1)-2,4-B8C2H10))(-) respectively. These compounds reacted with pyridine to give the nido-metallocarborane complexes which contain a bridge hydrogen atom. Oxidation of these complexes with Fe(III) afforded the complexes which do not appear to contain a bridge hydrogen and presumably contain the closo-CoB8C2H9:C5H5N polyhedron. (Author)

The reaction of bis-(pi-(3)-1,2-B9C2H11)2Co(-1) with aqueous base at 100C and in the presence of added Co(+2) produced (in low yield) two polymetal complexes which contain the bidentate pi-bonding B8C2H10(-4) ion. The preparation and properties of these two complexes, (B9C2H11CoB8C2H10CoB9C2H11)(-2) and (B9C2H11CoB8C2H10CoB8C2H10-CoB9C2H11)(-3) are described. (Author)