Two monoclonal antibodies were produced against the nucleoproteins of two strains of infectious hematopoietic necrosis virus (IHNV), One antibody, 1NDW14D, obtained by immunizing BALB/c mice with the nucleoprotein from Dworshak IHNV strain DW2, universally recognized IHNV in tests of direct and indirect fluorescence. The second antibody, 2NH105B, obtained by immunization with the nucleoprotein from an IHNV strain isolated from rainbow trout Oncorhynchus mykiss (formerly Salmo gairdneri) in the Hagerman Valley, Idaho, recognized biochemical type-2 IHNV. Both antibodies, 1NDW14D and 2NH105B, when conjugated with fluorescein, can be used in a direct fluorescence test that is more rapid than the previous methods of detecting the virus.

A characterization of the antigenic determinants (epitopes) of the glycoprotein (G) of infectious hematopoietic necrosis virus was made by expressing different regions of the G gene in Escherichia coli. A cDNA copy of the G gene was divided into four fragments by TaqI digestion, and the fragments were subcloned into pATH vectors, placing the expression of each G gene fragment under control of the trpE promoter. The resulting plasmids, pXL2, pXL3, and pXL7, encoded trpE-G fusion proteins subsequently detected with anti-infectious hematopoietic necrosis virus sera by Western immunoblots. A comparison of reactivities of the fusion proteins encoded by these plasmids was made by Western immunoblot and radioimmunoassay with a number of anti-G specific monoclonal antibodies (MAbs). The nonneutralizing MAb 136J reacted with the trpE-G fusion protein encoded by pXL3 and fusion proteins encoded by plasmids p52G and p618G, which were described in previous

Outer membranes (OMs) of Salmonella enteritidis, S. anatum, S. typhimurium, and S. infantis were extracted and cross-linked with glutaraldehyde to form a large macromolecular antigen. The antigen consisted of OM proteins and lipopolysaccharide and was designated 4-OMP-LPS. Polyacrylamide gel electrophoresis of extracted OMs from each serotype revealed differences in protein profiles. S. enteritidis and S. infantis possessed a greater variety of proteins than did S. anatum and S. typhimurium. Immunizations with 4-OMP-LPS in phosphate-buffered saline (4-OMP-LPS-C) and 4-OMP-LPS emulsified with muramyl dipeptide in the oil phase of a hexadecane-water emulsion (4-OMP-LPS-MDP) revealed that BALB/c mice were capable of eliciting specific primary and secondary immunoglobulin M (IgM) and IgG responses. Both antigen preparations were capable of eliciting IgM and IgG specific for the cell surfaces of each live Salmonella serotype. Also, 4-OMP-LPS-MDP and 4-OMP-LPS-C were capable of evoking a substantial anamnestic response. Adsorption studies revealed that the combined serotypes had the antigenic capacity to adsorb up to 94% of the antibodies, but 4-OMP-LPS-MDP antibodies were more effectively adsorbed than were 4-OMP-LPS-C antibodies. Adsorption of pooled antiserum with heterologous bacteria yielded a variety of adsorption profiles.

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A quick direct fluorescent antibody test incorporating a monoclonal antibody, 1NDW14D, reacting with the nucleoprotein of infectious hematopoietic necrosis virus (IHNV), revealed the presence of the 1989 Dworshak isolates of the virus 8 h after Chinook salmon embryo (CHSE-214) cells were incubated with fish homogenates containing the virus. An indirect fluorescence assay was performed to compare the ability of the anti-nucleoprotein antibody, 1NDW14D, with that of an anti-glycoprotein antibody, 3GH135L, to detect IHNV. Although the nucleoprotein of IHNV is synthesized before the glycoprotein, both antibodies detected the presence of virusinfected cells with equal efficiency when tested on several isolates of IHNV. Both antibodies stained caps of glycoprotein or nucleoprotein in the cytoplasm contiguous with the plasma membrane of infected cells within 6-8 h after infection.