When influenza virus was mixed with antisera to its surface subunits before inoculation of cell cultures, anti-hemagglutinin antibodies neutralized infectivity but anti-neuraminidase did not. When the antisera were added after infection of cell cultures, anti-hemagglutinin and anti-neuraminidase antibodies were equally effective in reducing virus titers in culture fluids. Decreased virus titers...

During the course of Plasmodium lophurae infections in normal chickens, there was a sharp increase in the titer of a hemagglutinin which reacted better with trypsinized than with normal erythrocytes. This hemagglutinin was a typical "cold hemagglutinin" in that it was much more active at 4 C than at 37 C, was found in the macroglobulin fraction of the serum, was eluted from erythrocytes at 37 C...

A xenogeneic antiserum raised to antireovirus immunoglobulin was used to define an idiotypic determinant present on antibodies to reovirus type 3 hemagglutinin. The same idiotype was identified on nonimmune lymphoid cells and on neuronal cells that specifically bind the hemagglutinin of type 3 reovirus. This idiotypic determinant, called Id3, is shared by (a) a monoclonal antibody to the neutra...

The host defense response to influenza infection is complex. Specific humoral antibodies develop to the strain-specific surface antigens, the hemagglutinin and the neuraminidase, and to the internal antigens (matrix and nucleoprotein) which are common to all influenza A viruses (1). Antibodies to the hemagglutinin, which is the major surface antigen, neutralize viral infectivity (2). In additio...

Fusion between P3 x 63 Ag8 mouse myeloma cells and spleen cells from BALB/c mice immunized with influenza type A or B or parainfluenza type 1 virus generated reproducibly antiviral antibody-producing somatic cell hybrids (hybridomas). Eleven hybridomas derived from spleen cells of mice immunized with influenza type A virus were directed against the viral hemagglutinin, one reacted with a host c...

The effect of mutations of Newcastle disease virus (NDV) fusion (F) gene, hemagglutinin-neuraminidase (HN) gene, and phosphoprotein (P) gene and HN chimeras between the virulent Beaudette C and low virulence LaSota strains on pathogenesis and pathogenicity was examined in fully susceptible chickens. A virulent F cleavage site motif within a LaSota backbone increased pathogenicity and severity o...

A gene in a genome is defined as putative alien (pA) if its codon usage difference from the average gene exceeds a high threshold and codon usage differences from ribosomal protein genes, chaperone genes and protein-synthesis-processing factors are also high. pA gene clusters in bacterial genomes are relevant for detecting genomic islands (GIs), including pathogenicity islands (PAIs). Four othe...

The effect of 1, l-diphenyl-2-propynyl cyclohexylcarbamate on hemagglutinin and hemolysin formation by mice in response to sheep red blood cells has been investigated. A single LDio dose of drug was administered at various times before or after immunization and the hemaggluti nin response was evaluated. With this dose the drug, de pending on time of administration in relation to primary immune ...