ABSTRACT
Sera obtained from 137 cervical cancer patients were analysed for the presence of antibodies to the human papillomavirus (HPV) type 16 proteins E6 and E7 by the aid of different assays, i.e. ELISA using as antigen either synthetic peptides or the complete E7 protein and radio-immunoprecipitation (RIPA) which uses the viral protein made by in vitro transcription/translation. In agreement with previous reports, reactivity to the E7 protein was found more frequently than to the E6 protein (31.4% vs. 16.8%) when the sera were assayed by peptide-based ELISA. In contrast, when RIPA was employed, reactivity to either protein was obtained at similar frequency (38.7% vs 46.7%). When the protein was denatured prior to immuno-precipitation the reactivity was lost in all sera tested for E6-specific antibodies but only in a few samples in the E7-RIPA. Therefore it was concluded that the increased sensitivity of the E6-RIPA as compared to the E6 peptide-ELISA is due to the detection of antibodies to conformational epitopes which are presented by the in vitro product but not by the synthetic peptides. Eighty-two sera from healthy donors were tested by HPV 16E6- and E7-RIPA and also by ELISA using the HPV 16E7 protein which was produced in the fission yeast Schizosaccharomyces pombe. One sample reacted each in the E6- and E7-RIPA indicating a high specificity of these assays. The E7 protein-ELISA proved to be less sensitive for the detection of antibodies in cervical cancer patients' sera (22.6% positive) as compared to peptide-based ELISA or RIPA.
Subject(s)
Antibodies, Viral/blood , Oncogene Proteins, Viral/immunology , Papillomaviridae/immunology , Repressor Proteins , Uterine Cervical Neoplasms/immunology , Adolescent , Adult , Aged , Aged, 80 and over , Carcinoma, Squamous Cell/immunology , Carcinoma, Squamous Cell/virology , Case-Control Studies , Enzyme-Linked Immunosorbent Assay/methods , Epitopes/chemistry , Epitopes/immunology , Female , Humans , Male , Middle Aged , Papillomavirus E7 Proteins , Protein Conformation , Radioimmunoprecipitation Assay , Recombinant Proteins/immunology , Sensitivity and Specificity , Uterine Cervical Neoplasms/virologyABSTRACT
In this paper are reported the effects of organophosphate pesticide exposure. Agricultural workers were compared with an age- and sex-matched control group selected from the general population. A significant difference was detected (Student's t = 1.99, p = .05) between the median activity levels of serum cholinesterase in agricultural workers at the end of the work day (mean 4.44, 95% CI = 4.12-4.77), compared with those in the control group (mean = 4.85, 95% CI = 4.57-5.13). The decrease in cholinesterase activity, measured at the beginning (mean = 4.70, 95% CI = 4.38-5.02) and end of the work day, was very significant (paired t = 2.70, p = .01). An interaction was identified between the type of work and the worker's age. Younger workers tended to perform more dangerous activities, and they experienced a greater decrease in cholinesterase activity. This study indicates that subclinical intoxication of agricultural workers, by pesticides, is occurring in Mexico and indicates the need for primary prevention programs that address occupational contact with such substances.
