antibody(6) immunization(6) Combination(6) Vaccine(6) immune response(6) Antigen(6) robust(4) Antibody Response(4) provided(4) Receptor binding domain(4) circumvent(4) RBD(4) binding(4) Protein-subunit vaccine(4) hydroxide(4) SARS-CoV-2(4) neutralize(4) caused(4) elicit(4) global pandemic(4) expression(4) Memory antibody response(4) lactic acid(4) mammalian(4) COVID-19 vaccine(4) Result(4) Th1(4) expressed(4) memory(4) mimicking(4)