PCR4 Antibody

Antibody Structure and Function

The first source provides foundational insights into antibody structure, emphasizing the role of the hinge region in IgG subclasses (e.g., IgG4 Fab-arm exchange) and protease sensitivity. While this offers context on antibody engineering, it does not reference "PCR4 Antibody."

Key Findings:

• IgG4 antibodies undergo natural Fab-arm exchange, enabling bispecificity .

• Hinge region mutations can confer resistance to proteases like MMP-3 and cathepsin G .

Anti-CTLA-4 Antibodies and Isotype Effects

Key Findings:

• IgG2a anti-CTLA-4 reduces intratumoral Tregs by 75% within 5 days post-treatment .

• IgG1 and IgG1-D265A (FcγR-binding deficient) show no antitumor activity .

CD4+ T Cells in Viral Immunity

The third source highlights CD4+ T cells' role in antiviral immunity, including their helper functions for B cells and CD8+ T cells. No mention of "PCR4 Antibody" is present.

Key Findings:

• CD4+ T cells are critical for generating long-lived antibody responses and memory CD8+ T cells .

• Memory CD4+ T cells exhibit enhanced effector functions during re-infection .

Anti-PF4 Antibodies in VITT

The fourth source describes reverse-engineered anti-PF4 antibodies (e.g., CR22047) associated with vaccine-induced thrombotic thrombocytopenia (VITT). These antibodies target the PF4 heparin-binding site, with residue R22 identified as a key epitope. Again, "PCR4 Antibody" is absent.

Key Findings:

• R22 is critical for PF4 binding, with K62 and K66 as secondary epitope residues .

• Clonotypic IgG1 anti-PF4 rAbs activate platelets via FcγRIIa .

Broadly Neutralizing HIV Antibody (3BNC117)

The fifth source evaluates 3BNC117, a HIV-1-neutralizing antibody, in clinical trials. No reference to "PCR4 Antibody" is made.

Key Findings:

• 3BNC117 neutralizes 195/237 HIV-1 strains across 6 clades (IC50: 0.08 μg/ml) .

• CD4+ T-cell counts increased by 39 cells/μl in HIV-1-infected participants post-infusion .