Perubahan Kadar IL-4 Hepar pada Mencit BALB/c Pasca Injeksi Protein Pili 65,5 kDa Klebsiella Pneumoniae

Abstract

Klebsiella pneumoniae is an opportunistic Gram-negative bacterium responsible for severe infections such as pneumonia, sepsis, and hepatic abscess, and is associated with high mortality rates. The increasing prevalence of multidrug resistance has limited therapeutic options, emphasizing the need for preventive approaches such as vaccine development. One promising antigen is the 65.5 kDa pili protein, which exhibits immunogenic properties. Interleukin-4 (IL-4), a cytokine involved in Th2 regulation, B-cell activation, and anti-inflammatory responses in the liver, was selected as an immunological marker in this study. This research aimed to evaluate the effect of the 65.5 kDa pili protein on hepatic IL-4 levels in BALB/c mice. An experimental randomized post-test only controlled group design was used. Mice were divided into three groups: K1 (PBS), K2 (PBS + Freund’s adjuvant), and K3 (PBS + Freund’s adjuvant + 65.5 kDa pili protein). Inductions were performed intraperitoneally on days 0, 14, and 28. On day 42, the mice were terminated, and liver tissues were analyzed for IL-4 concentration using ELISA. The results showed that the K3 group had the highest IL-4 levels. One-way ANOVA revealed significant differences among groups (p < 0.05). Post hoc Tukey tests indicated that IL-4 levels in the PBS control group (K1) were significantly lower than those in both the adjuvant group (K2) and antigen group (K3), while no significant difference was found between K2 and K3. In conclusion, administration of the 65.5 kDa pili protein of K. pneumoniae increased hepatic IL-4 levels in BALB/c mice, although the difference was not significant compared to adjuvant administration. These findings highlight the immunomodulatory potential of the 65.5 kDa pili protein and support its development as a vaccine antigen candidate against K. pneumoniae. Further studies are recommended to measure baseline IL 4 levels prior to antigen induction, extend sampling times to capture the full dynamics of IL-4 production, and evaluate different antigen doses in combination with adjuvants to determine optimal immunogenicity and safety profiles. In addition, the use of epitopes instead of crude protein is recommended to generate a more specific immune response.