[Effect difference between two segments in invariant chain CLIP on humoral immune]

Area of Science:

• Immunology
• Molecular Biology
• Vaccine Development

Background:

• Invariant chain (Ii) plays a crucial role in antigen presentation.
• Specific segments of Ii, such as the cytosolic (Cyt) and transmembrane (TM) domains, can be engineered for immune modulation.
• Class II-associated invariant chain peptide (CLIP) is a key component within the Ii structure.

Purpose of the Study:

• To compare the immunomodulatory effects of two invariant chain (Ii) segments, PBS and GBS, within an immune carrier system.
• To evaluate the impact of these Ii segments on humoral immune responses.
• To determine the optimal Ii segment for enhancing immune responses when combined with a Newcastle disease virus (NDV) epitope.

Main Methods:

• Reconstruction of six hybrid constructs incorporating NDV epitope F2 and Ii segments (Cyt/TM/F2, Cyt/TM/F2/GBS, Cyt/TM/PBS/F2, Cyt/TM/F2/TRIM, Cyt/TM/F2/GBS/TRIM, Cyt/TM/PBS/F2/TRIM).
• Expression of recombinant fusion proteins in E. coli using the pET-32a vector.
• Immunization of mice with purified fusion proteins and subsequent detection of specific antibody titers using ELISA.

Main Results:

• All hybrid constructs significantly increased antibody titers compared to the F2 epitope alone (1.5-fold to 4.9-fold increase).
• Hybrids containing either PBS or GBS segments showed higher antibody titers (1.6-fold to 2.4-fold increase) compared to those lacking these segments.
• The hybrid construct containing the PBS segment exhibited a 1.5-fold higher antibody titer than the GBS segment hybrid.

Conclusions:

• The cytosolic and transmembrane domains of the invariant chain (Ii) effectively enhance immune responses.
• The PBS segment of Ii demonstrates superior efficacy over the GBS segment in an Ii-based immune carrier system.
• Engineering Ii segments holds promise for developing more effective vaccine carriers.