Prokaryotic Expression, In Vitro Biological Analysis, and In Silico Structural Evaluation of Guinea Pig IL-4.

Area of Science:

• Immunology
• Molecular Biology
• Structural Biology

Background:

• Interleukin-4 (IL-4) is a key cytokine produced by T-helper type 2 (Th2) cells, crucial for modulating immune responses.
• The role of IL-4 in the guinea pig model, relevant for tuberculosis (TB) research, remains largely uncharacterized.
• A need exists to characterize IL-4 in guinea pigs to better understand immune mechanisms in this model.

Purpose of the Study:

• To clone and express the guinea pig IL-4 gene.
• To verify the authenticity and biological activity of the recombinant guinea pig IL-4 (rgpIL-4) protein.
• To predict the three-dimensional structure of guinea pig IL-4 and compare it to human IL-4.

Main Methods:

• Gene cloning and expression of guinea pig IL-4 using a prokaryotic expression vector (pET30 a(+)).
• Mass spectrometry for protein size confirmation and polyclonal anti-IL-4 antiserum for authenticity verification.
• Biological activity assay in RAW264.7 cells and homology modeling using the human IL-4 structure.

Main Results:

• Successfully expressed a 19 kDa recombinant guinea pig IL-4 (rgpIL-4) protein.
• Confirmed protein authenticity using specific antibody binding and demonstrated biological activity by suppressing nitric oxide production.
• Homology modeling revealed structural similarity between guinea pig and human IL-4, with 58% sequence homology.

Conclusions:

• The successful expression of biologically active rgpIL-4 provides a valuable tool for immunological studies.
• This recombinant protein can enhance the understanding of guinea pig immune responses to infectious diseases like TB.
• The structural insights offer a basis for comparative immunology and potential therapeutic target identification.