Protective intestinal anti-rotavirus B cell immunity is dependent on alpha 4 beta 7 integrin expression but does not require IgA antibody production

Rotavirus (RV) is the main cause of severe gastroenteritis in young children; protection has been correlated with intestinal Ab responses. Using a mouse model of RV infection and beta(7)-deficient (beta(7)(-/-)) mice, which do not express alpha(4)beta(7) integrin, we demonstrated the importance of alpha(4)beta(7) integrin in B cell-mediated anti-RV immunity. beta(7)(-/-) mice acutely infected with murine RV resolved infection and developed normal serum IgG Abs but had diminished intestinal IgA responses. alpha(4)beta(7)(-/-) immune B cells did not resolve RV infection when adoptively transferred into RV-infected Rag-2-deficient mice. Fewer RV-specific B cells were found in the intestine of Rag-2-deficient mice transferred with beta(7)(-/-) B cells compared with wild type. The absence of alpha(4)beta(7) expression and/or a lower frequency of IgA-producing cells among transferred beta(7)(-/-) B cells could have accounted for the inability of these cells to resolve RV infection following passive transfer. To distinguish between these possibilities, we studied the importance of IgA production in RV infection using IgA-deficient (IgA(-/-)) mice. IgA(-/-) mice depleted of CD8(+) T cells were able to clear primary RV infection. Similarly, adoptive transfer of immune IgA(-/-) B cells into chronically infected Rag-2-deficient mice resolved RV infection. We further demonstrated in both wild-type and IgA(-/-) mice that, following oral RV infection, protective B cells reside in the alpha(4)beta(7)(high) population. Our findings suggest that alpha(4)beta(7) integrin expression is necessary for B cell-mediated immunity to RV independent of the presence of IgA.     

Vaccination with recombinant vaccinia viruses expressing ICP27 induces protective immunity against herpes simplex virus through CD4+ Th1+ T cells.

This study was designed to evaluate the efficacy and mechanisms of protection mediated by recombinant vaccinia viruses encoding immediate-early (IE) proteins of herpes simplex virus type 2 (HSV-2). Three mouse strains were immunized against the IE proteins ICP27, ICP0, and ICP4, and mice were challenged intracutaneously in the zosteriform model with HSV-2 strain MS. Protection was observed only following immunization with the ICP27 construct and then only in the BALB/c mouse strain. Protection in BALB/c mice was ablated by CD4+ T-cell suppression but remained intact in animals depleted of CD8+ T cells. Moreover, protection could be afforded to SCID nude recipients with CD4+ but not CD8+ T cells from ICP27-immunized mice. Only BALB/c mice developed a delayed-type hypersensitivity reaction to HSV-2, and in vitro measurements of humoral and cell-mediated immunity revealed response patterns to ICP27 and HSV that differed between protected BALB/c and unprotected mouse strains. Accordingly, BALB/c responses showed antigen-induced cytokine profiles dominated by type 1 cytokines, whereas C57BL/6 and C3H/HeN mice generated cytokine responses mainly of the type 2 variety. Our results may indicate that protection against zosterification is mainly mediated by CD4+ T cells that express a type 1 cytokine profile and that protective vaccines against HSV which effectively induce such T-cell responses should be chosen.     

Structure of RecX protein complex with the presynaptic RecA filament: Molecular dynamics simulations and small angle neutron scattering

Using molecular modeling techniques we have built the full atomic structure and performed molecular dynamics simulations for the complexes formed by Escherichia coli RecX protein with a single-stranded oligonucleotide and with RecA presynaptic filament. Based on the modeling and SANS experimental data a sandwich-like filament structure formed two chains of RecX monomers bound to the opposite sides of the single stranded DNA is proposed for RecX::ssDNA complex. The model for RecX::RecA::ssDNA include RecX binding into the grove of RecA::ssDNA filament that occurs mainly via Coulomb interactions between RecX and ssDNA. Formation of RecX::RecA::ssDNA filaments in solution was confirmed by SANS measurements which were in agreement with the spectra computed from the molecular dynamics simulations.     

Modulation of Viral Immunoinflammatory Responses with Cytokine DNA Administered by Different Routes

The efficacy of plasmid DNA encoding cytokine administered by different routes, systemic or surface exposure, was evaluated and compared for their modulating effects on subsequent lesions caused by infection with herpes simplex virus (HSV). Systemic or topical administration of both interleukin-4 (IL-4) and IL-10 DNA but not IL-2 DNA caused a long-lasting suppression of HSV-specific delayed-type hypersensitivity response. IL-4 or IL-10 DNA preadministration also modulated the expression of immunoinflammatory lesions associated with corneal infection of HSV. Suppression of ocular lesions required that the DNA be administered to the nasal mucosa or ocular surfaces and was not evident after intramuscular administration. The modulating effect of IL-10 DNA was most evident after topical ocular administration, whereas the effects of IL-4 DNA given by both routes appeared to be equal. Preexposure of IL-4 DNA, but not IL-10 DNA, resulted in a significant change in Th subset balance following HSV infection. Our results indicate that the modulating effect of IL-4 or IL-10 DNA may proceed by different mechanisms. Furthermore, our results suggest that surface administration of cytokine DNA is a convenient means of modulating immunoinflammatory lesions.     

Enhancement of somatic embryogenesis in orchardgrass leaf cultures by epinephrine

Epinephrine at 10–100 M stimulated somatic embryogenesis from orchardgrass (Dactylis glomerata L.) leaves cultured on SH medium with 30 M of indole-3-acetic acid (IAA). Ethylene emanation was increased at epinephrine concentrations greater than 10 M. Decarboxylation by the leaves of [1-¹⁴C]IAA included in the medium was decreased almost 3-fold by 10 M epinephrine. Epinephrine at 10 M enhanced the number of regenerated plants on SH medium with 30 M dicamba (SH-30). Ethylene emanation was increased by epinephrine concentrations of 500 M and greater included in SH-30 but somatic embryogenesis was decreased. Addition of 8 M CoCl₂, 6H₂O (an ethylene biosynthesis inhibitor) to medium with 500 M epinephrine decreased ethylene emanation to the control level but did not alleviate the decreased embryogenic response.     

Seasonal dynamics of the trematodes fauna in herring gull (Larus argentatus Pontopp.) of Kola Bay

Trematode fauna of the herring gulls from Kola Bay (Barents Sea) was investigated in March, May, June, and September 2005. The data on the trematode species composition and indices of the invasion of gulls with trematodes are given for each season. It was established, that trematode species composition is increased from spring to summer, and intensity of the gulls' invasion with some trematode species is increased from summer to autumn. Ecological factors causing seasonal differences of the trematode fauna in gulls are discussed.     

Alfalfa embryo production in airlift vessels via direct somatic embryogenesis

A procedure for the development of alfalfa (Medicago falcata L.) somatic embryos to the torpedo stage in air-lift vessels is described. Embryos were initiated from chopped leaf explants and were formed by direct somatic embryogensis. The system produced a high number of torpedo stage embryos. The effect of various inoculation densities on embryo development was studied. A procedure for the development and maturation of embryos in aerated liquid media was established. The rate of conversion of the torpedo stage embryos formed in the vessels was 83%.Abbreviations ABA abscisic acid - B5 Gamborgs B5 medium (Gamborg et al. 1968) - COT cotyledon embryo state - 2,4-d 2,4-dichlorophenoxyacetic acid - FW fresh weight - ID internal diameter - MS Murashige and Skoog medium (Murashige & Skoog 1962) - PEG polyethylene glycol - POLY polyembryos - VVM volume of gas/volume of bioreactor