Intranasal Delivery of Cholera Toxin Induces Th17-Dominated T-Cell Response to Bystander Antigens

Cholera toxin (CT) is a potent vaccine adjuvant, which promotes mucosal immunity to protein antigen given by nasal route. It has been suggested that CT promotes T helper type 2 (Th2) response and suppresses Th1 response. We here report the induction of Th17-dominated responses in mice by intranasal delivery of CT. This dramatic Th17-driving effect of CT, which was dependent on the B subunit, was observed even in Th1 or Th2-favored conditions of respiratory virus infection. These dominating Th17 responses resulted in the significant neutrophil accumulation in the lungs of mice given CT. Both in vitro and in vivo treatment of CT induced strongly augmented IL-6 production, and Th17-driving ability of CT was completely abolished in IL-6 knockout mice, indicating a role of this cytokine in the Th17-dominated T-cell responses by CT. These data demonstrate a novel Th17-driving activity of CT, and help understand the mechanisms of CT adjuvanticity to demarcate T helper responses

The Tetraspanin Protein CD37 Regulates IgA Responses and Anti-Fungal Immunity

Immunoglobulin A (IgA) secretion by plasma cells in the immune system is critical for protecting the host from environmental and microbial infections. However, the molecular mechanisms underlying the generation of IgA+ plasma cells remain poorly understood. Here, we report that the B cell–expressed tetraspanin CD37 inhibits IgA immune responses in vivo. CD37-deficient (CD37−/−) mice exhibit a 15-fold increased level of IgA in serum and significantly elevated numbers of IgA+ plasma cells in spleen, mucosal-associated lymphoid tissue, as well as bone marrow. Analyses of bone marrow chimeric mice revealed that CD37–deficiency on B cells was directly responsible for the increased IgA production. We identified high local interleukin-6 (IL-6) production in germinal centers of CD37−/− mice after immunization. Notably, neutralizing IL-6 in vivo reversed the increased IgA response in CD37−/− mice. To demonstrate the importance of CD37—which can associate with the pattern-recognition receptor dectin-1—in immunity to infection, CD37−/− mice were exposed to Candida albicans. We report that CD37−/− mice are evidently better protected from infection than wild-type (WT) mice, which was accompanied by increased IL-6 levels and C. albicans–specific IgA antibodies. Importantly, adoptive transfer of CD37−/− serum mediated protection in WT mice and the underlying mechanism involved direct neutralization of fungal cells by IgA. Taken together, tetraspanin protein CD37 inhibits IgA responses and regulates the anti-fungal immune response

A BEAM-FOIL STUDY OF LITHIUM

Bien qu'il existe plusieurs explorations des niveaux doublement excités du Li et sa séquence isoélectronique, il y a encore des incertitudes concernant les schémas des termes. Récemment, différents auteurs ont présenté des calculs nouveaux sur les énergies des niveaux en Li I**, impliquant des reclassifications et aussi l'existence de transitions non déjà observées. Dans le diagramme des niveaux quelques-unes de ces transitions forment des boucles fermées, dont on peut contrôler précisément la balance d'énergie pourvu que les longueurs d'ondes soient bien connues. En conséquence, nous avons fait un nouvel examen détaillé expérimental des spectres Li I-III dans la région 2000-5500 Å en employant la technique beam-foil. Environ 125 raies ont été registrées et soigneusement analysées en utilisant un programme d'ajustement par des gaussiennes. Des résultats sur les longueurs d'ondes, les intensités relatives et les déviations standards sont donnés.Although several investigations of doubly excited states in the Li isoelectronic sequence have been made, many uncertainties remain with the term schemes presented so far. Recently, many authors have presented new calculations of energy levels in Li I**, suggesting reclassifications and also the existence of transitions not previously observed. In the level diagram, some of the latter are members of closed loops which can be checked to a high degree of accuracy if the wavelengths are well known. We have, therefore, undertaken a thorough study of Li I-III spectra in the wavelength region 2000-5500 Å, using the beam-foil method. A total of about 125 lines have been recorded and carefully analyzed, using a Gaussian fitting routine. Wavelengths, relative intensities and standard deviations are deduced

RELATIVE LEVEL EXCITATION IN BEAM-FOIL EXCITED Li AND Be

Nous avons étudié des spectres beam-foil de Li et Be dans le domaine 200-550 nm de longueur d'ondes. Les populations relatives des différents niveaux de Rydberg de la même série de termes décroissent un peu plus rapidement que n-3, comme on a pu constater dans les collisions entre ions et atomes soumis à des conditions de collisions simples. La population relative des niveaux ayant le même numéro quantique principal croît quand les niveaux changent de s vers p, décroît de p vers d, et croît encore de d vers g.We have studied the optical beam-foil spectra of Li and Be in the wavelength region 200-550 nm. The relative population for different Rydberg levels of the same term series decreases somewhat faster than n-3, as is also observed in ion-atom encounters under single collision conditions. The relative level population for levels of the same principal quantum number increases from s to p levels, decreases from p to d, and increases again from d to g levels