RESUMO
Antivenoms have been widely used for more than a century for treating snakebites and other accidents with poisonous animals. Despite their efficacy, the use of heterologous antivenoms involves the possibility of adverse reactions due to activation of the immune system. In this paper, alternatives for antivenom production already in use were evaluated in light of their ability to minimize the occurrence of adverse reactions. These effects were classified according to their molecular mechanism as: anaphylactic reactions mediated by IgE, anaphylactoid reactions caused by complement system activation, and pyrogenic reactions produced mainly by the presence of endotoxins in the final product. In the future, antivenoms may be replaced by humanized antibodies, specific neutralizing compounds or vaccination. Meanwhile, improvements in antivenom quality will be focused on the obtainment of a more purified and specific product in compliance with good manufacturing practices and at an affordable cost.
RESUMO
Antivenoms have been widely used for more than a century for treating snakebites and other accidents with poisonous animais. Despite their efficacy, the use of heterologous antivenoms involves the possibility of adverse reactions due to activation of the immune system. In this paper, alternatives for antivenom production already in use were evaluated in light of their ability to minimize the occurrence of adverse reactions. These effects were classified according to their molecular mechanism as: anaphylactic reactions mediated by IgE, anaphylactoid reactions: aused by complement system activation, and pyrogenic reactions produced mainly by the presence of endotoxins in the final product. ln the future, antivenoms may be replaced by humanized antibodies, specific neutralizing compounds or vaccination. Meanwhile, improvements in antivenom quality will be focused on the obtainment of more purified and specific product in compliance with good manufacturing practices and at an affordable cost
Assuntos
Humanos , Antivenenos/efeitos adversos , Laboratórios , Mordeduras de Serpentes , Anafilaxia , EndotoxinasRESUMO
A glycoconjugate constituted by the Streptococcus pneumoniae serotype 14 capsular polysaccharide (CPS14) and bovine serum albumin (BSA) was prepared, and the unique properties of Sephadex LH-20 were used to separate the conjugate from the unconjugated material. The strength of this approach consists in its capacity to produce pure polysaccharide-protein conjugate in good yield and free from unconjugated material, a common residual contaminant of this type of immunobiologicals. The CPS14-BSA conjugate prepared via an improved 1-cyano-4-dimethylaminopyridinium tetrafluoroborate (CDAP)-activation technique was characterized chemically and its immunogenicity was evaluated in mice. The purified conjugate, unlike the corresponding polysaccharide, produced a T-cell-dependent response in this species.
Assuntos
Cápsulas Bacterianas/imunologia , Cápsulas Bacterianas/isolamento & purificação , Vacinas Bacterianas/isolamento & purificação , Glicoconjugados/síntese química , Glicoconjugados/isolamento & purificação , Streptococcus pneumoniae/imunologia , Animais , Feminino , Camundongos , Soroalbumina BovinaRESUMO
A competitive ELISA for potency determination of bothropic equine antivenom was developed and compared to the conventional in vivo ED(50) assay, with the aim of partially substituting the in vivo assay in the monitoring of antivenom immunoglobulin levels. On this purpose, blood samples were taken at different times during and after the immunization protocol of the lot of horses used for production of snake antivenom at the Instituto de Higiene, Uruguay. Both the competitive ELISA and the ED(50) assay were performed on those samples. In addition, a group of five commercial pepsin-digested antivenoms were tested by both methods. A significant (P<0.001) correlation (Pearson's r=0.957) was found between the ELISA titres and the corresponding ED(50) values, indicating that the in vitro test can estimate the neutralizing antibody capacity of the sera as well as the in vivo assay. By means of this new ELISA, it was found that the immunized animals maintained good venom antibody titres, in the order of 20-50% of the maximum achieved, even 10 month after the end of the immunization schedule. The main advantage of our ELISA design is its ability to correctly estimate the neutralization capacity of crude hyperimmune plasma and antivenom sera independently of their antibody composition in terms of whole IgG or F(ab')(2) fragment.
Assuntos
Antivenenos/sangue , Ensaio de Imunoadsorção Enzimática/métodos , Venenos de Serpentes/imunologia , Animais , Cavalos , Imunização , Testes de NeutralizaçãoRESUMO
Snake antivenom, an expensive animal product, is presently the only effective treatment for the consequences of snakebite. In Latin America, antivenoms are mainly produced by public institutions with frequent shortages of the necessary supply. Here, we present an economical analysis of the factors affecting production cost, assuming a basic processing batch of 100 L hyperimmune plasma. Three annual production volumes were considered for two typical production technologies. The components of cost were classified as fixed, variable and semi-variable. We found that in all stages of production, fixed cost represents the major contribution to total cost, and is given essentially by manpower cost, particularly for low production volumes. Our estimation shows that antivenom cost can vary from US$ 2.4 to US$ 25 per 10 mL vial, depending on the production volume, the plasma processing technology used and the titer achieved during the immunization stage. We conclude that interested laboratories and authorities of countries with population at risk should consider the possibility of a joint production to improve the process efficiency, lower the product unitary cost and obtain the necessary supply for their own demand or that of other countries in need.
RESUMO
Snake antivenom, an expensive animal product, is presently the only effective treatment for the consequences of snakebite. In Latin America, antivenoms are mainly produced by public institutions with frequent shortages of the necessary supply. Here, we present an economical analysis of the factors affecting production cost, assuming a basic processing batch of 100 L hyperimmune plasma. Three annual production volumes were considered for two typical production technologies. The components of cost were classified as fixed, variable and semi-variable. We found that in all stages of production, fixed cost represents the major contribution to total cost, and is given essentially by manpower cost, particularly for low production volumes. Our estimation shows that antivenom cost can vary from US$ 2.4 to US$ 25 per 10 mL vial, depending on the production volume, the plasma processing technology used and the titer achieved during the immunization stage. We conclude that interested laboratories and authorities of countries with population at risk should consider the possibility of a joint production to improve the process efficiency, lower the product unitary cost and obtain the necessary supply for their own demand or that of other countries in need
Assuntos
Humanos , Antivenenos/economia , Custos de Medicamentos/tendências , Setor Público/economiaRESUMO
We describe a rapid and efficient method for producing the capsular polysaccharide of Streptococcus pneumoniae by fermentation on tryptic soy broth and purification of this compound by using immobilized soybean lectin as an affinity adsorbent. In principle, the same strategy can be used to produce purified capsular polysaccharides from other streptococcal serotypes by selecting the appropriate lectin adsorbents.
Assuntos
Cápsulas Bacterianas/biossíntese , Cápsulas Bacterianas/isolamento & purificação , Cromatografia de Afinidade/métodos , Streptococcus pneumoniae/metabolismo , Cápsulas Bacterianas/química , Espectroscopia de Ressonância Magnética , Streptococcus pneumoniae/crescimento & desenvolvimentoRESUMO
Equine chorionic gonadotrophin (eCG) is a hormone of practical value in veterinary medicine and animal production. Here we report a novel preparation procedure based on its direct adsorption onto anionic-exchange resins in a batch-wise mode. The active plasma is previously conditioned to reduce pH and ionic strength to required levels. After the adsorption stage, a 90% recovery of the initial eCG is achieved, with a concentration factor of about 50 and an enrichment factor around 500, with high preservation of biological activity. Further purification is carried out by cation-exchange column chromatography. The recovery for the whole process is higher than 70%, and the final potency of the preparation is close to 4000 IU/mg. The process is well suited for its application to the industrial scale.