Apolipoprotein(a) (apo(a)) contains tandemly repeated kringle domains that are closely related to plasminogen kringle 4, followed by a single kringle 5-like domain and an inactive protease-like domain. Recently, the anti-angiogenic activities of apo(a) have been demonstrated both in vitro and in vivo. However, its effects on tumor angiogenesis and the underlying mechanisms involved have not been fully elucidated. To evaluate the anti-angiogenic and anti-tumor activities of the apo(a) kringle domains and to elucidate their mechanism of action, we expressed the last three kringle domains of apo(a), KIV-9, KIV-10, and KV, in Escherichia coli. The resultant recombinant protein, termed rhLK68, exhibited a dose-dependent inhibition of basic fibroblast growth factor-stimulated human umbilical vein endothelial cell proliferation and migration in vitro and inhibited the neovascularization in chick chorioallantoic membranes in vivo. The ability of rhLK68 to abrogate the activation of extracellular signal-regulated kinases appears to be responsible for rhLK68-mediated anti-angiogenesis. Furthermore, systemic administration of rhLK68 suppressed human lung (A549) and colon (HCT-15) tumor growth in nude mice. Immunohistochemical examination and in situ hybridization analysis of the tumors showed a significant decrease in the number of blood vessels and the reduced expression of vascular endothelial growth factor, basic fibroblast growth factor, and angiogenin, indicating that suppression of angiogenesis may have played a significant role in the inhibition of tumor growth. Collectively, these results suggest that a truncated apo(a), rhLK68, is a potent antiangiogenic and anti-tumor molecule.

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The development of COVID-19 vaccines is critical in controlling global health issues under the COVID-19 pandemic. The subunit vaccines are the safest and most widely used vaccine platform and highly effective against a multitude of infectious diseases. An adjuvant is essential for subunit vaccines to enhance the magnitude and durability of immune responses. In this study, we determined whether a combination of toll-like receptor (TLR)1/2 and TLR3 agonists (L-pampo) can be a potent adjuvant for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) subunit vaccine. We measured a neutralizing antibody (nAb) and an angiotensin-converting enzyme 2 (ACE2) receptor-blocking antibody against SARS-CoV-2 receptor-binding domain (RBD). We also detected interferon-gamma (IFN-γ) production by using ELISPOT and ELISA assays. By employing a ferret model, we detected nAbs and IFN-γ producing cells and measured viral load in nasal wash after the challenge of SARS-CoV-2. We found that SARS-CoV-2 antigens with L-pampo stimulated robust humoral and cellular immune responses. The efficacy of L-pampo was higher than the other adjuvants. Furthermore, in the ferret model, SARS-CoV-2 antigens with L-pampo elicited nAb response and antigen-specific cellular immune response against SARS-CoV-2, resulting in substantially decreased viral load in their nasal wash. Our study suggests that SARS-CoV-2 antigens formulated with TLR agonists, L-pampo, can be a potent subunit vaccine to promote sufficient protective immunity against SARS-CoV-2.

IntroductionIndividuals deficient in mannose-binding lectin (MBL), an important component of the innate immune system, show increased susceptibility to infection. We investigated whether polymorphisms in the MBL2 gene and the serum level are associated with the severity and prognosis of sepsis.MethodsA total of 266 patients with sepsis and 398 healthy controls were enrolled. We analyzed the three single nucleotide polymorphisms (Gly54Asp, -550, and +4) in the MBL2 gene. Serum samples collected on day 1 were analyzed for the levels of MBL.ResultsPatients who were heterozygous (A/B) or homozygous (B/B) at codon 54 (adjusted odds ratio (OR), 0.370; 95% confidence interval (CI), 0.207-0.661, P = 0.001) and who were heterozygous (H/L) or homozygous (L/L) at -550 (adjusted OR, 0.476; 95% CI, 0.249-0.910, P = 0.025) were less likely to have septic shock in the sepsis group. Using Cox regression analysis for 28-day mortality, an MBL level ≥ 1.3 microg/mL showed significantly lower 28-day mortality (P = 0.020; hazard ratio, 0.571; 95% CI, 0.355-0.916) in the septic shock group.ConclusionsHomozygosity at codons 54 (A/A) and -550 (H/H) appears to be associated with the severity, but not the outcome, of sepsis, whereas a low MBL level may be an independent risk factor for mortality. These findings suggest that the genotype and serum level for MBL2 may have different clinical implications.

Summary Coupling between certain pathogen‐associated molecular patterns and corresponding pattern recognition receptors of endothelial cells is important for the mediation of vascular inflammatory responses. Mannose‐binding lectin (MBL) recognizes certain carbohydrate structures of microbes and subsequently activates the complement system as well as facilitates the phagocytosis of targets. We investigated whether MBL can intervene in the interaction between bacterial lipopolysaccharide (LPS) and endothelial cells to modulate subsequent inflammatory responses. In response to LPS, human umbilical vein endothelial cells (HUVEC) produced various cytokines/chemokines. Addition of the purified human MBL/MBL‐associated serine proteases (MASP) complex or recombinant human MBL enhanced LPS‐mediated cytokine/chemokine secretion by HUVEC, including interleukin‐8 (IL‐8), IL‐6 and monocyte chemoattractant protein‐1 in a dose‐dependent manner. This enhancing effect was ameliorated by the addition of anti‐MBL antibody or mannan. Among the cytokines/chemokines we analysed, IL‐6 showed the greatest increase of secretion in the presence of native MBL/MASP complex or recombinant MBL. MBL, regardless of its association with MASP, alters LPS‐mediated cytokine/chemokine secretion of HUVEC. Besides the well‐known functions of MBL, to activate the lectin–complement pathway and to facilitate clearance of targets, alteration of cytokine/chemokine secretion may provide an additional role for MBL in modulating vascular inflammation.