Objective Previous reports have demonstrated immune responses in guinea pigs (GP) exposed to animal-derived surfactants. In separate studies, immune responses were observed in GP challenged with Survanta®¹ and Curosurf.² We assess potential for immune response to KL4-surfactant, a wholly synthetic peptide-containing surfactant, in GP immune potentiated with adjuvant.

Methods GP were divided into 5 groups. Groups 1–4 were immunized subcutaneously (SQ) with either KL4-peptide (KL4) or Bovine Serum Albumin (BSA) in phospholipid (DPPC:POPG, 3:1) vehicle (PL) and Titre-Max™ adjuvant (Adj). Group 5 received intratracheal (IT) immunization of KL4-PL. 27 days later serum was obtained from GP in groups 1, 3, and 5 for passive cutaneous anaphylaxis (PCA) testing. At 28 days PG in groups 1 and 4 were challenged with IV BSA-PL, and groups 2, 3, and 5 were challenged with IV KL4-PL. Active anaphylaxis was determined using a 0–4 grading system for all GP for 20 minutes after challenge. PCA testing using the collected serum was performed in naïve GP receiving either IV BSA-PL or KL4-PL.

Results Anaphylaxis occurred only in GP immunized and challenged with BSA-PL-Adj (group 1), and PCA reaction occurred only with serum from this group with BSA-PL, but not KL4-PL. No anaphylaxis or PCA reaction was associated with any group receiving KL4-PL with immunization and/or challenge.

Conclusion The KL4 peptide does not induce an immune response, even under conditions of immune potentiation.

¹SBA for Survanta NDA 20-032, Pgs. 50–51.

²SBA for Curosurf, Pgs.35,38.

Supported by Discovery Labs, Inc.