An isolated human IgM antibody or fragment thereof which specifically binds neurons and protects neurons from cell death and which does not promote remyelination, wherein the isolated human IgM antibody or fragment comprises the following sequence: (a) the variable heavy chain amino acid CDR domain sequences CDR1 GGSVSLYY (SEQ ID NO:31), CDR2 GYIYSSGST (SEQ ID NO:32) and CDR3 ARSASIRGWFD (SEQ ID NO:33), and light chain CDR sequences CDR1 QSISSY (SEQ ID NO: 34), CDR2 AAS (SEQ ID NO:35) and CDR3 QQSYHTPW (SEQ ID NO:36), as set out in Figure 5; or (b) the variable heavy chain amino acid CDR domain sequences CDR1 GFTFSTYA (SEQ ID NO: 37), CDR2 INVGGVTT (SEQ ID NO:38) and CDR3 VRRSGPDRNSSPADF (SEQ ID NO:39), and light chain CDR sequences CDR1 QGIG (SEQ ID NO: 40), CDR2 TTS (SEQ ID NO:41) and CDR3 QKYNSAPRT (SEQ ID NO: 42), as set out in Figure 6, for use in a method of treating or ameliorating cerebral ischemia or stroke, improving neural function in an animal after stroke or cerebral ischemia, or in protecting neurons or neural cells from damage or cell death after stroke or cerebral ischemia, wherein the method comprises administering the isolated human IgM antibody or fragment thereof in combination with a remyelinating antibody, and wherein the remyelinating antibody comprises: (i) heavy chain variable region CDRs comprising CDR1 sequence SSGMH (SEQ ID NO: 47), CDR2 sequence V ISYDGSRKYYADSVKG (SEQ ID NO: 48) and CDR3 sequence GVTGSPTLDY (SEQ ID NO: 49), and light chain variable region CDRs comprising CDR1 sequence SGSSSNIGNNFVS (SEQ ID NO: 50), CDR2 sequence DITKRPS (SEQ ID NO: 51) and CDR3 sequence G TWDSSLSAW (SEQ ID NO: 52); or (ii) heavy chain variable region CDRs comprising CDR1 sequence SGFTFSSYW (SEQ ID NO: 53), CDR2 sequence IKKDGSEK (SEQ ID NO: 54) and CDR3 sequence ARPNCGGDCYLPWYFD (SEQ ID NO: 55), and light chain variable region CDRs comprising CDR1 sequence QSVLYSSNNKNY (SEQ ID NO: 56), CDR2 sequence YWAS (SEQ ID NO: 57) and CDR3 sequence QQYYNTPQA (SEQ ID NO: 58). (a) the variable heavy chain amino acid CDR domain sequences CDR1 GGSVSLYY (SEQ ID NO:31), CDR2 GYIYSSGST (SEQ ID NO:32) and CDR3 ARSASIRGWFD (SEQ ID NO:33), and light chain CDR sequences CDR1 QSISSY (SEQ ID NO: 34), CDR2 AAS (SEQ ID NO:35) and CDR3 QQSYHTPW (SEQ ID NO:36), as set out in Figure 5; or (b) the variable heavy chain amino acid CDR domain sequences CDR1 GFTFSTYA (SEQ ID NO: 37), CDR2 INVGGVTT (SEQ ID NO:38) and CDR3 VRRSGPDRNSSPADF (SEQ ID NO:39), and light chain CDR sequences CDR1 QGIG (SEQ ID NO: 40), CDR2 TTS (SEQ ID NO:41) and CDR3 QKYNSAPRT (SEQ ID NO: 42), as set out in Figure 6, (i) heavy chain variable region CDRs comprising CDR1 sequence SSGMH (SEQ ID NO: 47), CDR2 sequence V ISYDGSRKYYADSVKG (SEQ ID NO: 48) and CDR3 sequence GVTGSPTLDY (SEQ ID NO: 49), and light chain variable region CDRs comprising CDR1 sequence SGSSSNIGNNFVS (SEQ ID NO: 50), CDR2 sequence DITKRPS (SEQ ID NO: 51) and CDR3 sequence G TWDSSLSAW (SEQ ID NO: 52); or (ii) heavy chain variable region CDRs comprising CDR1 sequence SGFTFSSYW (SEQ ID NO: 53), CDR2 sequence IKKDGSEK (SEQ ID NO: 54) and CDR3 sequence ARPNCGGDCYLPWYFD (SEQ ID NO: 55), and light chain variable region CDRs comprising CDR1 sequence QSVLYSSNNKNY (SEQ ID NO: 56), CDR2 sequence YWAS (SEQ ID NO: 57) and CDR3 sequence QQYYNTPQA (SEQ ID NO: 58).