Self-amplifying mRNA SARS-CoV-2 vaccines raise cross-reactive immune response to variants and prevent infection in animal models.

The spike (S) protein of SARS-CoV-2 plays a crucial role in cell entry, and the nucleocapsid (N) protein is highly conserved among human coronavirus homologs. For potentially broad effectiveness against both original virus and emerging variants, we developed Alphavirus-based self-amplifying mRNA (sa-mRNA) SARS-CoV-2 vaccines: an sa-mRNA S encoding a full-length S protein stabilized in a prefusion conformation and an sa-mRNA S-N co-expressing S and N proteins for the original virus. We show that these sa-mRNA SARS-CoV-2 vaccines raised potent neutralizing antibody responses in mice against not only the original virus but also the Alpha, Beta, Gamma, and Delta variants. sa-mRNA S vaccines against the Alpha and Beta variants also raised robust cross-reactive neutralizing antibody responses against their homologous viruses and heterologous variants. sa-mRNA S and sa-mRNA S-N vaccines elicited Th1-dominant, antigen-specific CD4+ T cell responses to S and N proteins and robust and broad CD8+ T cell responses to S protein. Hamsters immunized with either vaccine were fully protected from lung infection and showed significant reduction of viral load in upper respiratory tract. Our findings demonstrate that sa-mRNA SARS-CoV-2 vaccines are potent in animal models with potential to be highly effective against SARS-CoV-2 infection in humans.

A case series using methylene blue for sentinel lymph node biopsy in breast cancer at St. Luke's Medical Center

Sentinel lymph node biopsy has not gained popularity in the Philippines, perhaps the reason being the unavailability of resources. The use of methylene blue may change this situation.OBJECTIVE: The authors intend to demonstrate that methylene blue may be used as an alternative dye in sentinel lymph node biopsy for breast cancer with satisfactory results.METHODS: Twenty patients diagnosed with breast cancer underwent sentinel lymph node biopsy after injection with methylene blue dye, followed by complete axillary dissection. Histologic evaluation of the nodes was done using H&E stain.RESULTS: The identification rate was 95%, with no false negatives.CONCLUSION: Sentinel lymph node biopsy using methylene blue can be done with satisfactory results.