Antibodies with specificity to native gp120 and neutralization activity against primary human immunodeficiency virus type 1 isolates elicited by immunization with oligomeric gp160.

Current human immunodeficiency virus type 1 (HIV-1) envelope vaccine candidates elicit high antibody binding titers with neutralizing activity against T-cell line-adapted but not primary HIV-1 isolates. Serum antibodies from these human vaccine recipients were also found to be preferentially directed to linear epitopes within gp120 that are poorly exposed on native gp120. Systemic immunization of rabbits with an affinity-purified oligomeric gp160 protein formulated with either Alhydrogel or monophosphoryl lipid A-containing adjuvants resulted in the induction of high-titered serum antibodies that preferentially bound epitopes exposed on native forms of gp120 and gp160, recognized a restricted number of linear epitopes, efficiently bound heterologous strains of monomeric gp120 and cell surface-expressed oligomeric gp120/gp41, and neutralized several strains of T-cell line-adapted HIV-1. Additionally, those immune sera with the highest oligomeric gp160 antibody binding titers had neutralizing activity against some primary HIV-1 isolates, using phytohemagglutinin-stimulated peripheral blood mononuclear cell targets. Induction of an antibody response preferentially reactive with natively folded gp120/gp160 was dependent on the tertiary structure of the HIV-1 envelope immunogen as well as its adjuvant formulation, route of administration, and number of immunizations administered. These studies demonstrate the capacity of a soluble HIV-1 envelope glycoprotein vaccine to elicit an antibody response capable of neutralizing primary HIV-1 isolates.     

The effect of lysolecithin on prostanoid and platelet-activating factor formation by human gall-bladder mucosal cells

It has been demonstrated that lysolecithin (lysophosphatidyl choline, LPC) produces experimental cholecystitis in cats mediated by arachidonic acid metabolites. LPC is a cytolytic agent that has been postulated as a contributing factor in the development of cholecystitis in humans. The purpose of this research was to evaluate the effect of LPC on human gall-bladder mucosal cell phospholipase A(2) and cyclooxygenase activity. Gall-bladder mucosal cells were isolated from the gall-bladders of patients undergoing routine cholecystectomy. Fresh, isolated cells were maintained in tissue culture and stimulated with varying doses of LPC. Platelet-activating factor concentration was quantitated as an index of phospholipase A(2) activity and prostanoids were measured as an index of cyclooxygenase activity. Also, the effect of LPC on cyclooxygenase 1 and 2 expression in microsomal protein was evaluated. LPC caused dose related increases in 6-keto-PGF(1alpha) and PAF produced by human gall-bladder mucosal cells. Exposure of human gall-bladder mucosal cells to LPC failed to elicit expression of constitutive cyclooxygenase-1, while the expression of inducible cyclooxygenase-2 was increased. The results of this study indicate that LPC induces the formation of prostanoids and PAF by human gall-bladder mucosal cells, suggesting that this substance may promote the development of gall-bladder inflammation.     

Hemotypes and genetic structure of Camargue horses

The nature and distribution of hemotypes constituted by electrophoretic phenotypes in six loci, in a group of 183 Camargue horses, have been compared with those of five breeds of horses and ponies. The genetic similarities have been observed mainly with New Forest and Haflinger ponies, less with Barbs and Thoroughbreds, and the least with Arab horses.     

Hsp27 is a mediator of sustained smooth muscle contraction in response to bombesin.

We have identified the low MW 27 kD heat shock protein as a major phosphoprotein constituent of smooth muscle and have investigated its potential role in agonist induced smooth muscle contraction. The neuropeptides bombesin and substance P, which are present in neurons of the anorectal region, induce contraction of isolated smooth muscle cells from this region by activating different intracellular pathways. Substance P-induced contraction is 1,4,5-inositol trisphosphate (IP3)/calmodulin dependent, while contraction induced by bombesin is mediated by a protein kinase C (PKC)-dependent pathway. The sustained contraction induced by bombesin or exogenous PKC was blocked by preincubation of cells with monoclonal antibodies to hsp27, while the transient contraction induced by substance P or IP3 was unaffected by the antibodies. Preincubation with isotype matched control antibodies had no inhibitory effect on contraction induced in response to the agents used. These data support a novel role for hsp27 in the non calmodulin mediated sustained contraction induced by bombesin or PKC.     

Identification and quantitation by radioimmunoassay of prostaglandin F compounds in bile

Separation and identification of prostaglandins in canine bile was performed by extraction and thin layer chromatography. The system provided tentative identification of the prostaglandin F compounds as the major prostaglandin subgroup present in bile. The prostaglandin was subsequently purified on silicic acid columns and quantitated by radioimmunoassay with tritiated PGF_2α and anti PGF_2α antibody employing the double antibody technique. Basal levels in hepatic bile were found to be 1028 ± 98 pg/ml.     

Influenza virus evades innate and adaptive immunity via the NS1 protein

Both antibodies and T cells contribute to immunity against influenza virus infection. However, the generation of strong Th1 immunity is crucial for viral clearance. Interestingly, we found that human dendritic cells (DCs) infected with influenza A virus have lower allospecific Th1-cell stimulatory abilities than DCs activated by other stimuli, such as lipopolysaccharide and Newcastle disease virus infection. This weak stimulatory activity correlates with a suboptimal maturation of the DCs following infection with influenza A virus. We next investigated whether the influenza A virus NS1 protein could be responsible for the low levels of DC maturation after influenza virus infection. The NS1 protein is an important virulence factor associated with the suppression of innate immunity via the inhibition of type I interferon (IFN) production in infected cells. Using recombinant influenza and Newcastle disease viruses, with or without the NS1 gene from influenza virus, we found that the induction of a genetic program underlying DC maturation, migration, and T-cell stimulatory activity is specifically suppressed by the expression of the NS1 protein. Among the genes affected by NS1 are those coding for macrophage inflammatory protein 1beta, interleukin-12 p35 (IL-12 p35), IL-23 p19, RANTES, IL-8, IFN-alpha/beta, and CCR7. These results indicate that the influenza A virus NS1 protein is a bifunctional viral immunosuppressor which inhibits innate immunity by preventing type I IFN release and inhibits adaptive immunity by attenuating human DC maturation and the capacity of DCs to induce T-cell responses. Our observations also support the potential use of NS1 mutant influenza viruses as live attenuated influenza virus vaccines.     

Histological Processing in Autoradiography: Loss of Radioactivity

Histological methods suitable for use in autoradiographic technics are described. An investigation has been carried out on the amount of activity lost from rat and human tissues during fixation and dehydration. Losses in the processing fluids varied from 25% to 90% of the initial activity for radioactive phosphorus and 4% to 20% for radioactive iodine in various fixatives.

The care necessary in handling sections if distribution of total activity is being studied is emphasized and floating on absolute alcohol is suggested as an alternative to warm mercury. Various procedures for staining sections before application of photographic emulsion and after developing are discussed. Ehrlich's hematoxylin applied regressively has given good results and eosin has been used successfully as a counterstain. Orth's lithium carmine is resistant to photographic developer and also Feulgen's stain counterstained with fast green can be used before covering the slides with photographic emulsion.