The prevalence of FeLV and FIV in healthy cats may have been substantially overestimated in some previous Australian surveys. FeLV infection would appear to be a rare cause of disease in Australian cats. The higher prevalence of FIV positivity in sick as opposed to healthy cats infers that FIV infection contributes to the development of disease.

This study was performed to characterize the antigen(s) recognized by a panel of monoclonal antibodies (MAbs) produced to be specific for Porphyromonas gingivalis whole cells which we had previously shown to bind to epitopes recognized by sera from periodontitis patients. Preliminary data had suggested that the argininespecific proteases of P. gingivalis (ArgI, ArgIA, and ArgIB) contained the antigenic determinants of four of these antibodies (MAbs 1A1, 2B/H9, 7D5, and 3B1). The location of the binding sites was examined with purified P. gingivalis enzymes and recombinant regions of the ArgI polyprotein expressed by subclones of the prpR1 gene in Escherichia coli XL-1 Blue cells. All four antibodies were reactive with protein determinants within the ␤ subunit, a hemagglutinin and/or adhesin component, of the ArgI dimer. MAb 1A1 strongly inhibited the agglutination of human erythrocytes by P. gingivalis W50 culture supernatant, suggesting that the binding site for this antibody contains residues which are critical for the interaction with the erythrocyte surface. The determinant for MAb 1A1 was examined further by construction of a set of truncated forms of the ␤ component expressed as fusion proteins with glutathione S-transferase at the N terminus. Analysis of these constructs mapped the binding site for MAb 1A1 to PrpRI residues G-907 to T-931, GVSPKVCKDV TVEGSNEFAP VQNLT. Western blot (immunoblot) analysis of P. gingivalis whole-cell proteins demonstrated that MAb 1A1 reacts with several proteins in the M r range of 20,000 to 120,000. Furthermore, an oligonucleotide probe corresponding to the coding sequence for the region of the ArgI ␤ component containing the MAb 1A1 binding site hybridized to multiple bands on genomic digests of P. gingivalis DNA. These data indicate that the MAb 1A1 epitope may be a component of a binding domain common to multiple gene products of this organism and may thus represent a functionally important target of the host's specific immune response to P. gingivalis in periodontal disease.

We have previously demonstrated that Porphyromonas gingivalis is susceptible to killing by toluidine blue O (TBO) when irradiated with light from a helium-neon (HeNe) laser. The aim of this study was to determine whether a TBO-antibody conjugate (Ab-TBO) could be used to specifically target P. gingivalis to lethal photosensitization in the presence of Streptococcus sanguis or human gingival fibroblasts (HGFs). When a mixture of P. gingivalis and S. sanguis was exposed to 4 g of TBO/ml and irradiated with HeNe laser light, there were 1.5-and 4.0-log 10 -unit reductions in the viable counts, respectively. In contrast, when TBO was conjugated with a murine monoclonal antibody against P. gingivalis lipopolysaccharide, the reductions in viable counts of P. gingivalis and S. sanguis amounted to 5.0 and 0.1 log 10 units, respectively. Lethal photosensitization of P. gingivalis in the presence of HGFs using unconjugated TBO resulted in a 0.7-log 10 -unit reduction in P. gingivalis viable counts and a 99% reduction in the incorporation of tritiated thymidine ([ 3 H]Tdr) by the HGFs. In contrast, when the Ab-TBO conjugate was used, there was a 100% reduction in P. gingivalis viable counts but no significant reduction in the incorporation of [ 3 H]Tdr by HGFs. These results demonstrate that specific targeting of P. gingivalis can be achieved using TBO conjugated to a monoclonal antibody raised against a cell surface component of this organism.

No abstract

Human papillomavirus type 16 (HPV-16) can cause genital warts, cervical dysplasias and carcinoma of the cervix. Cell-mediated immunity is thought to be important in protection against the virus and in its elimination, but little is known about the mechanisms involved. In a cross-sectional study we have demonstrated proliferative T cell responses to peptides representing the HPV-16 L1 capsid protein (aa 199-409) in the peripheral blood of 63% of patients (n = 41) with histological evidence of cervical dysplasia and in 45 % of healthy age-matched controls (n = 11). This was achieved by generating short-term T cell lines (STLs) from each individual in vitro against a fl-galactosidase-HPV-16 L1 (aa 199-409) fusion protein for 2 weeks, and then identifying the HPV epitopes they recognized with overlapping synthetic peptides (15-mers) spanning this region in 3 day specificity assays. Histological grading and HPV typing by PCR were performed on patients' cervical biopsies taken at the same clinical visit as the peripheral blood samples. An immunogenic region was identified between aa 311-345 in 73 % of patients (18 % in controls) who responded to HPV-16 L1 (aa 199-409). The number ofresponders to this region was significantly higher in patients with HPV-16-positive biopsies when compared to those with HPV-16-negative biopsies (P = 0.006), as was the number of responders to individual peptides 311-325 (NLASSNYFPTPSGSM; P = 0"04) and321-335 (PSGSMVTSDAQIFNK;P = 0.004)representing this region. The mean level of response to each individual peptide was also higher in the patient group than the controls (P < 0.05). The most significant finding was that all patients with evidence of a current HPV-16 infection responded to one or more L1 peptides (P = 0-0004) and 92 % had high grade cervical intraepithelial neoplasia (CIN III). We also found that the CIN III group was more likely to respond to any L1 peptide than either the atypical group (P = 0.04) or the controls (P = 0.05). Data from four individuals showed that the majority of peptide-specific STLs were CD4 + but some CD8 ÷ STLs were also detected.