The present disclosure relates to a recombinant gram-negative bacterial cell comprising: a) a mutant spr gene encoding a spr protein having a mutation at one or more amino acids selected from D133, H145, H157, N31, R62, I70, Q73, C94, S95, V98, Q99, R100, L108, Y115, V135, L136, G140, R144 and G147 and b) a gene capable of expressing or overexpressing one or more proteins capable of facilitating protein folding, such as FkpA, Skp, SurA, PPiA and PPiD, wherein the cell has reduced Tsp protein activity compared to a wild-type cell, methods employing the cells, use of the cells in the expression of proteins in particular antibodies, such as anti FcRn antibodies and proteins made by the methods described herein.

Mice having a restricted immunoglobulin heavy chain locus are provided, wherein the locus is characterized by a single polymorphic human V.sub.H gene segment, a plurality of human D.sub.H gene segments and a plurality of J.sub.H gene segments. Methods for making antibody sequences that bind an antigen (e.g., a viral antigen) are provided, comprising immunizing a mouse with an antigen of interest, wherein the mouse comprises a single human V.sub.H gene segment, a plurality of human D.sub.H gene segments and a plurality of J.sub.H gene segments, at the endogenous immunoglobulin heavy chain locus.

Provided is a method for producing trimeric and tetrameric IgA antibodies, the method including mixing dimeric IgA antibodies and monomeric IgA antibodies.

The present invention relates to methods exogenous nucleic acid molecules, such as RNA, that encode an antibody or antigen-binding fragment of an antibody, and optionally encode a cellular modulation factor and/or a potentiation factor. The cellular modulation factor is a factor that results in increased expression of the antibody and/or antigen-binding fragment. The potentiation factor is a factor that provides desired antibody effector or other properties. The exogenous nucleic acid molecules can be DNA or RNA, as mRNA (including self-replication RNA and non-self-replicating RNA). The invention also relates method for administering the exogenous nucleic acid molecules to a subject to achieve production of the encoded antibody or antigen-binding fragment in the subject to provide, for example, prophylactic or therapeutic passive immunity.

The invention provides methods and compositions useful for identifying polypeptides with desired characteristics in vitro.

The disclosure provides rabbit monoclonal antibodies against the spike S1 protein of SARS-CoV-2 and uses thereof. The antibody comprises: a V.sub.H CDR1 selected from the group consisting of SEQ ID NO: 1-7; a V.sub.H CDR2 selected from the group consisting SEQ ID NO: 8-14; a V.sub.H CDR3 selected from the group consisting of SEQ ID NO: 15-21; a V.sub.L CDR1 selected from the group consisting SEQ IDN NO: 22-28; a V.sub.L CDR2 selected from the group consisting of SEQ ID NO: 29-35; and a V.sub.L CDR3 selected from the group consisting of SEQ ID NO: 36-42. The antibodies can be used for a rapid test or screening of SARS-CoV-2 infection. The antibodies can also be used for treating SARS-CoV-2 infection.

The disclosure provides rabbit monoclonal antibodies against the nucleocapsid protein of SARS-CoV-2 and uses thereof. The antibody comprises: a V.sub.H CDR1 selected from the group consisting of SEQ ID NO: 1-7; a V.sub.H CDR2 selected from the group consisting SEQ ID NO: 8-14; a V.sub.H CDR3 selected from the group consisting of SEQ ID NO: 15-21; a V.sub.L CDR1 selected from the group consisting SEQ ID NO: 22-28; a V.sub.L CDR2 selected from the group consisting of SEQ ID NO: 29-35; and a V.sub.L CDR3 selected from the group consisting of SEQ ID NO: 36-42. The antibodies can be used for a rapid test or screening of SARS-CoV-2 infection and detecting SARS-CoV-2 nucleocapsid protein.

The invention relates to an immunoglobulin composition reduced in thrombogenic agents and to methods for its preparation. One method comprises subjecting an immunoglobulin containing solution to a negative cation exchanger chromatography at a pH in the range of higher than 3.8 to equal to or lower than 5.3. The solution can also be subjected to a negative anion exchanger chromatography at a pH in the range of 7 to 8.2.

Disclosed is a vaccine comprising an immunogenic composition comprising a complex of AMA1 and RON2 (or a fragment thereof), which elicits an immune response to a Plasmodium species in a subject upon administration. The resulting immune response is sufficient to impede or prevent infection by a Plasmodium species.

The invention refers to a non-therapeutic method for producing antigen-specific B cells by using the adoptive cell transfer of primed B cells, especially of spleen cells including B cells of a previously immunized non-human animal and by administering an antigen of interest to a naïve non-human animal.