The disclosure provides anti-DENV antibodies and methods of making and using the same. Nucleic acids encoding the anti-DENV antibodies and host cells comprising the nucleic acids are also provided. The anti-DENV antibodies have uses that include treating DENV infection. The disclosure also provided polypeptides containing a variant Fc region and methods of making and using the same. Nucleic acids encoding the polypeptides and host cells comprising the nucleic acids are also provided. The polypeptides have uses that include treating a viral infection. Also claimed is a polypeptide comprising a Fc variant comprising at least one amino acid alteration in a parent Fc region, wherein the variant Fc region has a substantially decreased FcYR-binding activity and does not have a substantially decreased C1 q-binding activity when compared to the parent Fc region.