An interlaboratory study of the reproducibility and relevance of Episkin, a reconstructed human epidermis, in the assessment of cosmetics irritancy.

Reconstructed epidermal models are particularly suited to assessing the tolerance of cosmetic and dermatological products in vitro. Their production in kit form makes them available for screening both raw ingredients and finished products since a large amount of material can be tested whatever their physicochemical properties. However, two conditions must first be fulfilled: they must give reproducible results and be relevant to data obtained in vivo. We tested the reproducibility of data obtained using the Episkin(R) model [cytotoxicity evaluated by the MTT conversion and the release of one of the most active proinflammatory mediator, interleukin 1alpha(ILalpha)] on different batches and in various research laboratories. After topical application of sodium dodecyl sulfate (SDS) the overall variability of the IC(50) results was 14% of the mean value. Within a given centre and a given batch, the coefficient of variation attributable to the dispersion between kits was 6% for the SDS IC(50) determination and 7% for IL1alpha release measurement. The results obtained with Episkin were then compared with data from primary human skin irritancy testing (48-hr occlusion test and clinical assessment) and rabbit irritancy evaluation (Draize cutaneous test). Analysis of the results obtained with 38 cosmetic products (oils, gels, emulsions, mascaras and shaving foam, including 19 irritants) revealed good concordance with data obtained in humans. Considering the release of IL1alpha as in vitro parameter, the test sensitivity, specificity and concordance were 68, 79 and 74%, respectively.

[Defined media for hybridoma culture: do they really replace serum and why are they attractive?]. / Milieux définis pour la culture d'hybridomes: remplacent-ils réellement le sérum et en quoi sont-ils attractifs?

The cell culture efficiency of serum free media is still the main question which limits the use of such a product. However, the experience due to a long usage of serum free media allows to certify that for hybridomas the proliferation growth is often similar to the levels attained with serum. Antibodies secretion is also good or superior to the one obtained with classical media used in different culture devices like flasks and cytocultures. Finally the higher purity degree of monoclonal antibodies in the cell culture supernatant is also a major advantage of serum free media.

New purified Vero-cell vaccine prevents rabies in patients bitten by rabid animals.

The protective effect of a new, potentially economical tissue-culture rabies vaccine, purified vero-cell rabies vaccine (PVRV), was tested in 106 patients bitten by animals with proven rabies. 0.5 ml PVRV was given intramuscularly on days 0, 3, 7, 14, 28, and 91; 47 patients with severe exposure were also given 20 IU/kg human rabies immune globulin (HRIG). All patients are alive and well after 1 year. Side-effects of treatment were negligible. Rabies neutralising antibody (greater than or equal to 1.6 IU) was demonstrated on day 14 and persisted for 1 year in every case. There was no significant suppression of the antibody response by HRIG. If the untreated mortality is 15%, PVRV is 81% efficient in protecting patients against rabies encephalitis (95% confidence limit). PVRV is likely to replace human diploid-cell strain vaccine as the most widely used tissue-culture rabies vaccine.

Purified Vero cell rabies vaccine and human diploid cell strain vaccine: comparison of neutralizing antibody responses to post-exposure regimens.

Neutralizing antibody responses to conventional rabies post-exposure regimens of human diploid cell strain vaccine (HDCSV) and the new purified Vero cell rabies vaccine (PVRV) were compared in 58 healthy Thai veterinary students. The geometric mean titres (GMTs) of the group given HDCSV were slightly higher than those given PVRV, but on day 28 the peak GMTs of the two groups were statistically similar. The early antibody response to PVRV was unaffected by the addition of passive immunization, whereas the level of HDCSV response was reduced on day 14, so that there was no difference on that day between the GMTs of the two vaccine groups given HRIG. However, by day 91 the GMT of those given PVRV and HRIG was lower than in those given HDCSV alone or with HRIG. The appearance of antibody was less rapid than was observed in previous studies using multiple-site intradermal vaccination. Side effects were trivial. Our results confirm the promise of this new, potentially more economical tissue culture vaccine, but they suggest that the regimen could be improved.

Economical multiple-site intradermal immunisation with human diploid-cell-strain vaccine is effective for post-exposure rabies prophylaxis.

An economical post-exposure regimen of Mérieux human diploid-cell-strain vaccine (HDCSV) was compared with Semple vaccine (SV), the most widely used vaccine in Asia. 155 patients bitten by animals proved to be rabid received either conventional courses of SV (34 severe and 43 mild cases) or HDCSV, 0.1 ml intradermally, at eight sites on day 0, at four sites on day 7, and at one site on days 28 and 91 (36 severe and 42 mild cases). All severely bitten patients were given equine anti-rabies serum (EARS), 80 IU/kg on day 0. There were no deaths from rabies in either group. Follow-up was 97.5% at 1 year and 93% at 2 years. 88% of patients given HDCSV alone had detectable neutralising antibody on day 7 in contrast to 2% given SV alone. Antibody persisted until 1 year in all sera tested from HDCSV patients in contrast to only 48% of SV sera. The high dose of EARS resulted in pronounced suppression of response to HDCSV. There were no serious systemic side-effects but local side-effects were significantly more common in the SV group. The multiple-site intradermal HDCSV regimen was at least as effective as SV. The amount of HDCSV used was 30% of the conventional dose.