FIG. 1.

Prevention of CVB3 myocarditis and protection against lethal CVB3 challenge by intranasal immunization with various combinations of LTN and VP1 genes in chitosan formulations. (A) Schematic representation of VP1 and LTN DNA constructs. (B) One representative heart section was shown for each group (magnification: 100×). Four weeks after four doses of DNA immunization, mice were intraperitoneally challenged with 3LD₅₀ CVB3. Seven days later, heart tissues were collected and HE-stained sections were evaluated for the incidence of acute myocarditis. Heart tissues from normal mice were used as control. (C) Myocarditis was assessed as the percentage of the heart section with inflammation compared with the overall size of the heart section, with the aid of a microscope eyepiece grid. (D) Viral load in heart was determined by plaque forming unit (PFU) assays. *p<0.05. (E) The survival rate of mice was observed until day 28 following a lethal dose of CVB3 (5LD₅₀) challenge. CVB3, Coxsackievirus B3 type; LTN, lymphotactin; HE, hematoxylin and eosin.