The invention relates to an antibody or fragment thereof that is capable of specifically binding to and blocking TREM-1, wherein the antibody or fragment thereof is capable of blocking PGLYRP1-induced activation of TREM-1； wherein the antibody or fragment thereof comprises: a CDRH1 sequence corresponding to amino acid residues 31 to 35 (TYAMH) of SEQ ID NO: 6, wherein one of these amino acid residues may be substituted by a different amino acid residue； and/or a CDRH2 sequence corresponding to amino acids 50 to 68 (RIRTKSSNYATYYAASVKG) of SEQ ID NO: 6, wherein one, two or three of said amino acids may be substituted with a different amino acid residue； and/or a CDRH3 sequence corresponding to amino acid residues 101 to 110 (DMGQRRQFAY) of SEQ ID NO: 6, wherein one, two or three of said amino acid residues may be substituted by a different amino acid； and wherein the antibody or fragment thereof comprises: a CDRL1 sequence corresponding to amino acid residues 24 to 38 (RASESVDTFDYSFLH) of SEQ ID NO: 7, wherein one, two or three of these amino acid residues may be substituted with a different amino acid； and/or a CDRL2 sequence corresponding to amino acid residues 54 to 60 (RASNLES) of SEQ ID NO: 7, wherein one or two of these amino acid residues may be substituted with a different amino acid； and/or a CDRL3 sequence corresponding to amino acid residues 93 to 101 (QQSNEDPYT) of SEQ ID NO: 7, wherein one or two of these amino acid residues may be substituted with a different amino acid
