The present invention provides an antibody which specifically recognizes an epitope containing a part of a domain based on a finding that the domain ranging from the 269- to 315-positions of human CD14 represented by SEQ ID NO:1 is a site capable of interacting with another protein, an antibodies provided. This antibody can inhibit the interaction between human CD14 and another protein and thus suppress cell activation. And also, the present invention provides hybridomas producing the above antibody or its fragment; a peptide containing the amino acids in the domain as specified above; a method of constructing an antibody with the use of this peptide as an immunogen; and a method of screening a medicament for sepsis involving the step of bringing a test substance into contact with CD14 and TLR.