Fig 1.
RP-HPLC chromatograms of venoms.
Families of the most abundant toxins in the venom fractions were identified according to previously published proteomic analyses: a) disintegrins, b) Kunitz-type inhibitors, c) bradykinin potentiating peptides, d) PLA2s, e) SVSPs, f) C-type lectin-like proteins and g) SVMPs.
Table 1.
Toxic activities of venoms of African Bitis and Echis species.
Fig 2.
Histological alterations in lungs induced by Bitis spp and Echis spp venoms in rabbits.
Immediately after euthanasia, lung samples were collected from rabbits immunized with venoms, and added to 3.7% formalin solution. After embedding the samples in paraffin, sections of 4 μm of thickness were obtained and stained with hematoxylin-eosin. Light micrographs correspond to sections obtained from rabbits immunized with the venoms of B. arietans (A), B. gabonica (B), E. coloratus (C) and E. ocellatus (D). Arrows depict areas with extravasated erythrocytes. Bar corresponds to 100 μm.
Fig 3.
Plasma activity of enzymes in rabbits immunized with venoms.
Plasma activity of A) creatine kinase (CK), B) alanine aminotransferase (ALT), and C) aspartate aminotransferase (AST) in plasma of rabbits immunized with venoms of B. arietans (B.a.), B. gabonica (B.g.), B. nasicornis (B.n.), B. rhinoceros (B.r.), E. coloratus (E.c.), E. leucogaster (E.l.), E. ocellatus (E.o.), and E. pyramidum (E.p.). Results are expressed in International Units (IU) / L and correspond to the mean ± SD (n = 4). *P < 0.05 when compared to the control group of non-immunized rabbits (Ctrl).
Fig 4.
Immunochemical cross-reactivity between anti-Bitis spp. sera.
Cross-reactivity between anti-Bitis spp. monospecific antisera and Bitis spp. venoms was determined by A) ELISA and B) Western blot. ELISA results are expressed as percentage, considering as 100% the titer of sera raised against the homologous venom of each species and correspond to the mean ± SD (n = 4). ↓ Heterologous sera with less than 33% content of specific antibodies of the corresponding homologous serum. LAAO: L-amino acid oxidases, SVMP: Zn2+-dependent snake venom metalloproteinases, SVSP: snake venom serine proteinases, CRISP: cysteine-rich secretory proteins, PLA2: phospholipases A2, CTL: C-type lectin-like proteins.
Fig 5.
Cross-neutralization of toxic activities of Bitis spp. venoms by monospecific antisera.
Cross-neutralization of A) lethal and B) hemorrhagic activities of Bitis spp. venoms. Only the antisera that gave higher than 33% cross-reactivity by ELISA were tested in these assays. Neutralization is expressed as ED50, i.e., mg venom neutralized per mL antivenom. In the case of lethality, error bars represent the 95% confidence intervals, while in the case of hemorrhage, error bars represent SD (n = 4). *Non-overlapping values with the anti-lethal 95% CI of the homologous serum, or no detectable ability to neutralize the hemorrhagic activity. ↓ heterologous sera that were no tested as they have less than 33% content of specific antibodies of the corresponding homologous serum.
Fig 6.
Immunochemical cross-reactivity between anti-Echis spp. sera.
Cross-reactivity between anti-Echis spp. monospecific antisera and Echis spp. venoms determined by A) ELISA and B) Western blot. ELISA results are expressed as a percentage, considering as 100% the titer of serum raised against the homologous venom of each species and correspond to the mean ± SD (n = 4). All heterologous antisera have > 33% content of specific antibodies of the corresponding homologous antiserum. LAAO: L-amino acid oxidases, SVMP: Zn2+-dependent snake venom metalloproteinases, SVSP: snake venom serine proteinases, CRISP: cysteine-rich secretory proteins, PLA2: phospholipases A2, CTL: C-type lectin-like proteins.
Fig 7.
Cross-neutralization of toxic activities of Echis spp. venoms.
Cross-neutralization of A) lethal, B) hemorrhagic, and C) coagulant activities of the Echis spp. venoms. Neutralization is expressed as ED50 (lethality and hemorrhage) and ED (coagulant effect), i.e., mg venom neutralized per mL antivenom. In the case of lethality, error bars represent the 95% confidence intervals, while in the case of hemorrhage and coagulation, error bars represent SD (n = 4). * Non-overlapping values with the anti-lethal 95% CI of the homologous serum, or no detectable or poor ability to neutralize hemorrhagic or coagulant activities.