Company: OCEA
Filing Date: 2025-04-08
Form Type: 10-K
Source: 0001641172-25-003155
Chunk: 2493

Company: Ocean Biomedical, Inc.
Filing Date: 2025-04-08
Form: 10-K
Item: Item 1
Chunk 2493
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 kill parasites. Polyclonal anti-PfSEA-1 antibodies in mice inhibit parasite growth by 74% in vitro. Ring stage
3D7 parasites were cultured in the presence of anti-PfSEA-1 mouse sera at 1:10 dilution. Negative controls included no anti-sera and
pre-immune mouse sera. Red blood cells (RBC).

In
vaccine challenge experiments in mouse models of malaria infection, immunization with a recombinant protein encoding the P. berghei ANKA
(a lethal mouse malaria strain) ortholog of PfSEA-1, or PbSEA-1, or antibodies to PbSEA-1 conferred marked protection against a lethal
P. berghei ANKA challenge as evidenced by up to a 75% reduction in parasitemia seven days after challenge. In all five experiments performed,
by day seven to eight after challenge, control mice had high parasitemia with associated morbidity, whereas none of the vaccinated mice
had high parasitemia or overt morbidity. In experiments with long-term follow-up, both active immunization with rPbSEA-1 and passive
transfer of antibodies to PbSEA-1 significantly reduced parasitemia and delayed mortality.

In
human observational studies conducted in Tanzania, individuals with naturally acquired antibodies to PfSEA-1 were associated with significant
protection from severe malaria, with no cases occurring while children had detectable antibodies to PfSEA-1 (Fig 9). In a second longitudinal
Kenyan cohort, anti–PfSEA-1 antibodies were associated with significant protection against parasitemia in adolescents and young
adults. Individuals with detectable IgG anti–rPfSEA-1 antibodies had 50% lower parasite densities over 18 weeks of follow-up compared
with individuals with no detectable IgG anti-rPfSEA-1A antibodies.

29

Figure
9. Antibodies to rPfSEA-1A predict reduced malaria severity and parasitemia. Incidence of severe malaria and death in Tanzanian children
aged one and a half to three and a half years during intervals with detectable and undetectable antibodies to PfSEA-1 (1688 and 23,806
weeks, respectively). No cases of severe malaria or death occurred during intervals with detectable antibodies to rPfSEA-1A. Error bars
represent 95% CI.

Based
on these data, we hypothesize that vaccination of humans with PfSEA-1 could generate antibodies that trap