SUMMARYWe have studied the role of three mouse distinct non-H-2 genes (Bcg, Tbc-1, xid ) in several phenomena of antituberculosis immunity and resistance. On the basis of median survival time (MST) of mice following infection with virulent Mycobacterium tuberculosis H37Rv, Bcg gene did not control resistance to the lethal dose of H37Rv infection in non-vaccinated and Myco. bovis (BCG)-vaccinated mice. However, Bcg r allele, in comparison with Bcg s allele, determined more effective suppression of an early multiplication in spleens of H37Rv mycobacteria after a low dose (5 2 10 4 colony-forming units (CFU)) injection. CBA/N mice, which are not protected efficiently against tuberculous challenge by BCG vaccination, were characterized by a decreased in vitro proliferation of immune lymph node cells, both spontaneous and stimulated with mycobacterial antigens. The decreased proliferation was due to immunosuppression caused by interactions between responding T cells and CBA/N antigen-presenting cells (APC). We have confirmed that the defective response to BCG-vaccination in CBA/N mice is linked with the X-chromosome and thus is presumably determined by the xid gene itself. I/St mice (Tbc-1 s ), supersusceptible to H37Rv infection, were not able to restrict the growth of H37Rv mycobacteria in spleens, even following infection with a low dose (5 2 10 4 ), but restricted the growth of Myco. bovis BCG more effectively than Bcg s mice.

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SUMMARYWe have studied the impact of distinct haplotypes and of difTerent alleles at specific H-2 loci on: (i) the susceptibility to lethal form of experimental tubereulosis; (ii) the level of DTH to mycobaclerial antigens; (iii) the efficacy of vaccination wilh bacille Calmette-Gucrin (BCG); and (iv) the IgG production and Tcell proliferative response to H37Rv antigens. On lhe basis of median survival lime (MST) following primary inoculation wilh lethal dose of Myeobaeterium tutwrcidosis, susceptibility to infection associated with I-A'' and // alleles. host resistance associaled with /-/I* and D'' alleles. Mice bearing a disease-resistant phenotype also developed a vigorous DTH response. Vaccination with BCG before H37Rv infection significantly prolonged the .survival time of both resistant and susceptible animals, except in BIO.M (H-2') mice. The latter exhibited intermediate resistance to infection before but slight decrease in lhe MST following a high-dose BCG vaccination. Distinct H-2 regulation of su.sceptibility to lethal infection and of BCG vaccination efiicacy was confirmed in another relatively resistant //-^'-bearing strain A.CA,, in which mortality occurred more rapidly in vaccinated compared with primarily infected animals. The expression of the H-2' haplotype was associated wilh a low DTH response to tuberculin following vaccination and subsequent lethal infection. The lack of BCG protection against Myco. tubercutosis QhaWcnofi'uy BIO.M mice associated with the high titre of specific IgG, In addilion, these mice exhibited a unique ability to respond to65-kD aniigen by both IgG synthesis and T cell proliferation.

Two monoclonal antibodies (mABs) raised against plum pox virus (PPV) were shown to recognize its D, M, and C strains. Conjugates of the antibodies with colloidal gold (CG) nanoparticles averaging 26 nm in diameter were synthesized. The binding constants of PPV with both the native and conjugated mABs were determined using a Biacore X device. The complexes between the CG-mAB conjugates and plum pox virions were examined by means of transmission electron and atomic force microscopy. Using the conjugates with optimal component ratio, an express immunochromatographic assay of PPV was developed with a detection limit of 3 ng/ml and duration of 10 min. The assay was tested for PPV detection in samples of stone fruit tree leaves and demonstrated a good compatibility with the data obtained by "sandwich"-ELISA. The developed assay can be used in the field and applied for monitoring viral infection and for quarantine purposes.

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