IMMUNE RESPONSE INDUCED BY NEW ADJUVANT STRATEGY TO PRODUCE CROTALIC ANTI-PLA2

LUCIANO FUSCO; ANDREA VAN DE VELDE; DAVID HERNANDEZ; SANTIAGO PALMA; BELKYS A. MALETTO; G MORON; LAURA CRISTINA LEIVA

Buenos Aires

Congreso; 20th World Congress of the International Society on Toxinology; 2019

Snake envenomation is a seriousmedical problem and antivenoms are the main treatment. Antisera are produced byimmunization of horses with snake venom using complete Freund?s adjuvant andincomplete (booster) but it causes severe local reactions. A new adjuvantstrategy is here proposed to increase efficiency in antisera production undermuch less morbilty to immunized animals. Previous works showed that CpG-ODNformulated with a 6-O-ascorbyl palmitate nanostructure (Coa-ASC16) was moreefficient as adjuvant than CpG-ODN alone using ovalbumin (OVA) as an antigenmodel. Here, we evaluated the immune response induced by this adjuvant strategyusing crotalic PLA2 enzymeas antigen. Balb/c mice were subcutaneously immunizated on days 0, 15 and 30with PLA2/CpG-ODN/Coa-ASC16or PLA2/Freund?s Adyuvant (complete first and incomplete-booster)(dose/mice: crotalic PLA2: 10-15μg, CpG-ODN: 30 μg). On day 50, mice weresacrificed. In both immunized group mice, the antibody titers in plasma were high(dilution1/24800), with a similar IgG1/IgG2a ratio. The IgG antibodies werethen purified by affinity Sepharose-proteinG column. Indirect hemolyticactivity neutralization of the PLA2(2.5 μg) with specific antibodies(1.7-4.5 μg range; IgG anti-PLA2) were made by radial hemolisis. Theevaluation did not show difference neutralizing capacity ofthe antibodies produced by CpG-ODN/Coa-ASC16 or Freund?s Adyuvant. Macroscopic andmicroscopic analysis at the site of injection of mice inoculated with Freund?sadjuvant showed local damage (with non-infectious abscesses) and hypertrophy ofinguinal lymph nodes, whereas mice injected with CpG-ODN/Coa-ASC16 did not. Our results showthat CpG-ODN/Coa-ASC16 produces ahumoral response as strong and specific as Freund´sadjuvant, with minor or nulllocal deleterious effect, So, this complex emerge as a new adjuvant, a veryattractive alternative for  anticrotalic sera production.@font-face{font-family:"Cambria Math";panose-1:2 4 5 3 5 4 6 3 2 4;mso-font-charset:0;mso-generic-font-family:roman;mso-font-pitch:variable;mso-font-signature:-536870145 1107305727 0 0 415 0;}@font-face{font-family:Calibri;panose-1:2 15 5 2 2 2 4 3 2 4;mso-font-charset:0;mso-generic-font-family:swiss;mso-font-pitch:variable;mso-font-signature:-536859905 -1073732485 9 0 511 0;}p.MsoNormal, li.MsoNormal, div.MsoNormal{mso-style-unhide:no;mso-style-qformat:yes;mso-style-parent:"";margin-top:0cm;margin-right:0cm;margin-bottom:10.0pt;margin-left:0cm;line-height:115%;mso-pagination:widow-orphan;font-size:11.0pt;font-family:"Calibri",sans-serif;mso-ascii-font-family:Calibri;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-hansi-font-family:Calibri;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;mso-fareast-language:EN-US;}.MsoChpDefault{mso-style-type:export-only;mso-default-props:yes;font-size:11.0pt;mso-ansi-font-size:11.0pt;mso-bidi-font-size:11.0pt;font-family:"Calibri",sans-serif;mso-ascii-font-family:Calibri;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-hansi-font-family:Calibri;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;mso-fareast-language:EN-US;}.MsoPapDefault{mso-style-type:export-only;margin-bottom:10.0pt;line-height:115%;}div.WordSection1{page:WordSection1;}