I am carrying out a study in which I will utilize vectored immunoprophylaxis (Adeno-associate virus based) to deliver a gene that codes for antibodies against a plasmodium sporozoite antigen into the liver BALB/C or C57BL/6 mice. I will then inject tail vein of the the mice with 10,000 radiation attenuated sporozoites to switch on the gene and trigger an immune response. Subsequently, I will need to inject the tail vein of the mice with wild-type virulent sporozoites to check if the VIP immunization was effective. I however do not know the number of wild-type sporozoites I need to inject the mice with,