Time and storage temperature influence in titer of anti rabies virus flourescent conjugate produced in Pasteur Institute - São Paulo

Abstract

Stability is defined as the period during which a product or reactant has, within specified limits, the same properties and characteristics possessed at the time of its manufacture. The determination of the validity ensures that the reagent maintains the characteristics of strength, purity and quality during the proposed period when stored under appropriate conditions. It is recommended for maintenance of conjugated polyclonal or antiribonucleoproteins rabies virus, at 4°C and protection of light incidence. The objective of this study was to evaluate the stability of the title of lots of rabies virus fluorescent conjugate produced at the Pasteur Institute of São Paulo (IP/SP), adequately stored for different periods and temperatures. The titles of the conjugates used in this study, so produced and maintained under appropriate conditions were determined by direct immunefluorescence (DIF) test on slides with decals of the central nervous system (CNS) of mice positive for rabies, and we used three batches, the which were named antiribonucleoproteins: February/2006 (L.RNP: 02/2006), rabies virus: January/2010 (L.TOT: 01/2010) and rabies virus: April/2011 (L.TOT: 04/2011), with titers 1:140, 1:100 and 1:80, respectively. Aliquots of these conjugates was also stored at – 20°C, after production. Aliquots kept at 4°C to – 20°C were evaluated by the IFD, in July 2012, using decals CNS of bovine positive for rabies, as the titers obtained aliquot (L.RNP: 02 / 2006), (L.TOT: 01/2010) and (L.TOT: 04/2011), after periods of storage at 4°C, 1:70, 1:80 and 1:80, and aliquots of the preserved -20°C, bonds 1:140, 1:100 and 1:100, respectively. The results of this study showed a small decrease of the title aliquots of conjugates produced in the IP/SP, when properly stored for long periods at 4°C, this may be due to changes in temperature through successive openings of the refrigerator, by observing better preservation of the titles of this reagent when aliquots are kept frozen, for single use at – 20°C without undergoing repeated thawing.