Pharmaceutical composition for preventing and healing epithelial lesions, immunomodulatory pharmaceutical composition, pharmaceutical composition for treating toxoplasmosis, pharmaceutical composition, insecticidal composition, insecticide, use of km + lectin to treat scarring, use of km + lectin to treat toxoplasmosis, use of km + lectin to prepare medicine to treat toxoplasmosis, use of km + lectin to prepare immunomodulatory drug, use of km + lectin to prepare antibacterial drug, use of km + lectin to prepare antiviral drug, expression method, DNA vector, recombinant organism, nucleotide sequence, proteins, antibodies and plasmids