ABSTRACT
Current influenza vaccines are believed to confer protection against a narrow range of virus strains. The identification of broadly influenza neutralizing antibodies (bnAbs) has triggered efforts to develop vaccines providing 'universal' protection against influenza. Several bnAbs were isolated from humans recently vaccinated with conventional influenza vaccines, suggesting that such vaccines could, in principle, be broadly protective. Assessing the breadth-of-protection conferred to humans by influenza vaccines is hampered by the lack of in vitro correlates for broad protection. We designed and employed a novel human-to-mouse serum transfer and challenge model to analyze protective responses in serum samples from clinical trial subjects. One dose of seasonal vaccine induces humoral protection not only against vaccine-homologous H1N1 challenge, but also against H5N1 challenge. This heterosubtypic protection is neither detected, nor accurately predicted by in vitro immunogenicity assays. Moreover, heterosubtypic protection is transient and not boosted by repeated inoculations. Strategies to increase the breadth and duration of the protective response against influenza are required to obtain 'universal' protection against influenza by vaccination. In the absence of known correlates of protection for broadly protective vaccines, the human-to-mouse serum transfer and challenge model described here may aid the development of such vaccines.
Subject(s)
Influenza Vaccines/immunology , Orthomyxoviridae Infections/immunology , Animals , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/immunology , Area Under Curve , Cell Line, Tumor , Cross Protection , Dogs , Female , Hemagglutination Inhibition Tests , Humans , Influenza A Virus, H1N1 Subtype/immunology , Influenza A Virus, H5N1 Subtype/immunology , Madin Darby Canine Kidney Cells , Mice , Mice, Inbred BALB C , Orthomyxoviridae Infections/mortality , Orthomyxoviridae Infections/prevention & control , ROC Curve , Seasons , VaccinationABSTRACT
Despite several efforts to standardize methods of semen analysis, sperm count is known to be subject to large interlaboratory differences. This is especially a problem in multicentre clinical trial settings and protocols for the preparation of semen for centralized assessment of sperm concentration are suggested here. The stability of semen has been tested after fixation with formalin at different dilutions and at different temperatures for different sperm concentrations. Sperm concentrations in formalin-fixed semen (at dilutions 1 + 0.5 to 1 + 19) were stable (<20% difference from original) at all concentrations (0.1 x 10(6)/mL to 100 x 10(6)/mL) for at least 5 days at room temperature and 4 degrees C. Prolonged stability up to 5 weeks at 4 degrees C was demonstrated for the lower dilutions (1 + 0.5 and 1 + 1). Freezing of fixed semen samples was unacceptable. These results illustrate that centralized assessment of sperm concentrations is feasible.
Subject(s)
Sperm Count/methods , Cold Temperature , Diagnostic Errors/prevention & control , Feasibility Studies , Fixatives , Formaldehyde , Humans , Male , Multicenter Studies as Topic , Quality Control , Specimen Handling/methods , Sperm Count/standardsABSTRACT
A series of MENT esters (3-71) was designed, prepared and tested to study the structure-activity relationship (SAR) of the hydrolysis rate with human liver microsomes of these prodrugs. Compounds were obtained covering a wide range of metabolic stability. The results are useful for the proper selection of prodrugs for different pharmaceutical formulations to deliver the potent and prostate-sparing androgen MENT. The MENT esters can especially be administered for male hormone replacement therapy and male contraception. Comparative molecular field analysis (CoMFA) was applied to a dataset of 28 esters, for which ED50 values could be obtained. The CoMFA model where the electrostatic and H-bond molecular fields were combined turned out to be most predictive. Despite the limited size of the dataset, CoMFA can help to rationalize the SAR of the ester hydrolysis rate of ester prodrugs of MENT.
