Immunogenicity testing is central to vaccine development, helping researchers determine whether a vaccine candidate can elicit a protective immune response. But for many assays, especially serum bactericidal assays (SBA) and opsonophagocytic killing assays (OPKA), the presence of naturally occurring antibodies in human serum sources can interfere with results. Pel-Freez has developed a scalable, validated method […]

New research addresses the need for Shigellosis vaccine development innovations Shigellosis remains a pressing global health challenge, particularly in low- and middle-income countries where it disproportionately affects children under five. This bacterial infection, caused by Shigella flexneri and other species, is a leading cause of diarrheal mortality and is further complicated by the rise of […]

Tackling the challenge of N. gonorrhoeae Neisseria gonorrhoeae, a pathogen with high infection rates and increasing antibiotic resistance, poses an urgent public health challenge. Despite decades of effort, vaccine development against this resilient bacterium has been limited by the absence of reliable in vitro correlates of immune protection. To address this, researchers from the FDA’s […]

We’re excited to announce that Pel-Freez Biologicals now offers pooled and single donor lyophilized human complement, making your lab work more efficient, cost-effective, and flexible. For years, Pel-Freez has provided high-quality lyophilized rabbit complement and other biological reagents. Now, we’re applying that same expertise to our native and antibody-depleted human complement, offering a freeze-dried product […]

Opsonophagocytic killing assays (OPKA/OPA) and multiplex OPKA (MOPA) evaluate the ability of antibodies to opsonize bacteria, facilitating their destruction by immune cells. Unlike ELISAs, which quantify antibodies, opsonophagocytic assays measure their functionality — specifically, whether they trigger immune responses that kill bacteria. For vaccines targeting encapsulated bacteria like S. pneumoniae, OPKA data are especially vital […]

One of our most popular offerings, double (IgG/IgM) depleted human serum, has been helping researchers perform vaccine development assays since 2017. Since then, we’ve scaled up our production processes to deliver large, multi-liter lot volumes and recently released a triple (IgG/IgM/IgA) depleted human serum. With so many available options (e.g., double vs. triple antibody depletion, […]