Anti-Chikungunya E1 Protein [Clone CHK-166] — Purified in vivo PLATINUM™ Functional Grade

Clone CHK-166 is a neutralizing monoclonal antibody that targets the E1 protein of chikungunya virus (CHIKV), and it is widely used in in vivo mouse studies for both prophylactic and therapeutic purposes, primarily in immunodeficient Ifnar^?/?^ mice, which lack type I interferon responses.

Key uses and details:

• Prophylaxis: CHK-166 is administered to mice (typically 10–50??g, intraperitoneally) one day prior to CHIKV infection. This pre-treatment provides complete protection against lethal CHIKV challenge in Ifnar^?/?^ mice.

• Therapeutic Use & Combination Therapy: When delivered as a single agent or in combination with another monoclonal antibody (e.g., CHK-152), CHK-166 can be administered post-infection. Combination therapy with CHK-166 and CHK-152 is especially effective; it prevents the emergence of viral escape mutants and extends the therapeutic window, allowing treatment at later timepoints after infection (up to 24–36 hours before predicted death).

• Escape Mutant Studies: CHK-166 is used to investigate the development of viral escape variants; it has been shown that pre-treatment with CHK-166 usually prevents the development of resistant virus variants, though rare escape mutants can emerge under therapeutic use.

• Mouse Models: Experimental studies use Ifnar^?/?^ mice and sometimes Rag1^?/?^ mice. Animals are commonly infected subcutaneously with 10–10^3^ FFU of CHIKV, and CHK-166 is given by intraperitoneal injection.

• Endpoints & Evaluation: Mice are monitored for survival, weight loss, clinical signs, and viral titers in relevant tissues to assess antibody efficacy.

In summary, CHK-166 is used primarily to protect mice from deadly CHIKV infection, to study immune escape, and as a tool for testing monoclonal antibody therapies in preclinical chikungunya research.

The correct storage temperature for sterile packaged clone CHK-166 is 2–8°C for up to one month. For longer-term storage, it should be aliquoted aseptically and stored at -80°C. Avoid repeated freeze-thaw cycles.

This recommendation aligns with general antibody storage guidelines and the available product-specific information for CHK-166, which is a purified monoclonal antibody packaged sterilely. If storage will extend beyond one month, ensure you aliquot the antibody without dilution before placing at -80°C to maximize stability and prevent contamination or degradation.

• Short-term storage (up to 1 month): 2–8°C (refrigerator)
• Long-term storage: Store at -80°C after aliquoting aseptically
• Precautions: Avoid repeated freeze-thaw cycles. Always check the specific lot datasheet if available for any additional notes on storage conditions.

Some of the most commonly used antibodies or proteins in combination with CHK-166 in the literature are CHK-152, CHK-102, CHK-263, and CHK-124. These monoclonal antibodies have been assessed in various combinations for their ability to prevent Chikungunya virus (CHIKV) infection or to provide therapeutic benefit in animal models.

Essential details and supporting information:

• CHK-152: CHK-166 is most frequently paired with CHK-152. Studies consistently highlight the combination of CHK-166 and CHK-152 as highly protective, outperforming monotherapy and other combinations in preventing lethality and viral resistance in Ifnar^?/?^ mice models. CHK-152 targets a neutralizing epitope on the CHIKV E2 protein.
• CHK-102: CHK-166 has also been combined with CHK-102, another potent neutralizing monoclonal antibody, which similarly increases protective efficacy and prevents escape mutants when used together.
• CHK-263: Combinations involving CHK-263 (e.g., CHK-263+CHK-152) have been tested for enhanced protection. CHK-263 is notable for binding epitopes across both E1 and E2 proteins, contributing to broad and potent neutralization.
• CHK-124: Structurally, CHK-124 is similar to other E2-targeting antibodies and has shown broad neutralization against CHIKV and related alphaviruses. While not as frequently combined directly with CHK-166 in published therapy studies, it is referenced as a structurally and functionally relevant anti-CHIKV antibody in comparative work.

Other related proteins or antibodies identified in the literature include:

• DENV1-E98: Used as a control antibody in comparative experiments.
• 5F10, CHK-265, RRV-12: Structurally characterized but not commonly reported in combination therapy with CHK-166.

Typically, these antibodies are selected for combination based on:

• Their distinct binding epitopes (minimizing escape mutations).
• Complementary mechanisms of viral neutralization.
• Synergistic protection observed in murine models.

In summary, CHK-152 is the most common partner for CHK-166 in both experimental and preclinical combination therapies, followed by CHK-102, CHK-263, and, to a lesser extent, CHK-124.

The primary scientific findings about clone CHK-166 highlight its role as a potent monoclonal antibody targeting the Chikungunya virus (CHIKV) E1 protein, demonstrating strong prophylactic and therapeutic efficacy in animal models and informing mechanisms of viral immune escape.

Key findings from CHK-166 literature:

• Epitope Specificity: CHK-166 binds to amino acids on domain II of the CHIKV E1 glycoprotein, situated next to the conserved fusion loop.
• Neutralizing Activity: CHK-166 acts as a neutralizing monoclonal antibody, providing complete protection against lethal CHIKV infection when administered prophylactically in Ifnar?/? mice. It also protects 63% of mice when given therapeutically (single dose 24 hours post-infection).
• Escape Mutations: Viral escape from CHK-166 results consistently in a single K61T mutation in the E1 protein; these escape variants were engineered and shown to inform antibody resistance in vitro and in vivo.
• Mechanism of Action: CHK-166 inhibits CHIKV infection after virus attachment in cell culture, through post-attachment neutralization.
• Combination Therapy: Co-administration of CHK-166 and another monoclonal antibody, CHK-152, after infection prevents viral resistance, extends the therapeutic window, and provides improved protection in animal models.
• Efficacy in Non-Human Primates: In rhesus macaques, combination CHK-152/CHK-166 therapy reduces viral spread to distant tissue sites, neutralizes reservoirs, and does not permit the development of escape mutants.

Additional context:

• The generation of CHK-166 involved infecting genetically modified mice with CHIKV and using hybridoma technology to isolate high-affinity antibodies targeting the viral E1 protein.
• CHK-166’s efficacy and escape profile have made it valuable for mapping neutralizing epitopes and understanding CHIKV immune evasion, supporting the rationale for antibody cocktail therapies.

In summary, CHK-166 is a highly specific, neutralizing monoclonal antibody against CHIKV E1, effective both alone and in combination therapy, with detailed characterization of its target epitope and escape mutations contributing to our understanding of chikungunya immunotherapeutics.