Phage Neutralization by Sera of Patients Receiving Phage Therapy

Abstract

The aim of our investigation was to verify whether phage therapy (PT) can induce antiphage antibodies. The antiphage activity was determined in sera from 122 patients from the Phage Therapy Unit in Wroc1aw with bacterial infections before and during PT, and in sera from 30 healthy volunteers using a neutralization test. Furthermore, levels of antiphage antibodies were investigated in sera of 19 patients receiving staphylococcal phages and sera of 20 healthy volunteers using enzyme-linked immunosorbent assay. The phages were administered orally, locally, orally/locally, intrarectally, or orally/intrarectally. The rate of phage inactivation (K) estimated the level of phages' neutralization by human sera. Low K rates were found in sera of healthy volunteers (K £ 1.73). Low K rates were detected before PT (K £ 1.64). High antiphage activity of sera K > 18 was observed in 12.3% of examined patients (n = 15) treated with phages locally (n = 13) or locally/orally (n = 2) from 15 to 60 days of PT. High K rates were found in patients treated with some Staphylococcus aureus, Pseudomonas aeruginosa, and Enterococcus faecalis phages. Low K rates were observed during PT in sera of patients using phages orally (K £ 1.04). Increased inactivation of phages by sera of patients receiving PT decreased after therapy. These results suggest that the antiphage activity in patients' sera depends on the route of phage administration and phage type. The induction of antiphage activity of sera during or after PT does not exclude a favorable result of PT.

Immunogenicity Studies of Proteins Forming the T4 Phage Head Surface

“…The effect may depend on such conditions as route of immunization, dose, additives, etc. (35). Further, the immunological response to an antigen in a living organism engages many other (not only humoral) components of the immunological system.…”

Phage engineering: how advances in molecular biology and synthetic biology are being utilized to enhance the therapeutic potential of bacteriophages

“…Similar results were obtained by Capparelli et al who found that serially passaged mutants of an environmental isolate of an E. coli O157:H7 phage and a Staphylococcus aureus phage were able to persist in the circulation up to 10 times longer (up to one month post-inoculation) than the wild-type and, interestingly, did not induce the formation of neutralizing antibodies [57,58]. A study by Łusiak-Szelachowska et al has analysed the presence of phage neutralising antibodies in human patients undergoing phage therapy, and found that whilst the level of antibody stimulation was inconsistent among the group, 12.3% of patients exhibited a strong phage neutralising response upon treatment, although this did not exclude a positive patient outcome [59]. It therefore may not be necessary to engineer phage such as to reduce the antiphage immune response in all cases, and could depend on the type of phage (replicative or non-replicative), the specific bacterial infection to be treated, route of administration, and planned number of phage administrations per treatment.…”

Phage therapy: awakening a sleeping giant

“…In fact, use of the 'filamentous' phage ΦX174 has been described since the 1960s as a method to assess specific antibody responses in patients with immunodeficiencies [47]. Low numbers of pre-existing serum antiphage antibodies toward tailed phages have also been demonstrated [46,48,49], which is not surprising with the high frequency of natural contact that humans have with tailed phages [43]. It has also been demonstrated that antibodies can be generated toward phages given therapeutically to treat bacterial infection in human [49] and animal [48,50].…”

“…Low numbers of pre-existing serum antiphage antibodies toward tailed phages have also been demonstrated [46,48,49], which is not surprising with the high frequency of natural contact that humans have with tailed phages [43]. It has also been demonstrated that antibodies can be generated toward phages given therapeutically to treat bacterial infection in human [49] and animal [48,50]. Antiphage antibodies have been found to have an affinity for specific viral structural components, for instance, against the non-essential highly immunogenic outer capsid (Hoc) protein of T4-like phages [48][49][50].…”

“…It has also been demonstrated that antibodies can be generated toward phages given therapeutically to treat bacterial infection in human [49] and animal [48,50]. Antiphage antibodies have been found to have an affinity for specific viral structural components, for instance, against the non-essential highly immunogenic outer capsid (Hoc) protein of T4-like phages [48][49][50]. In contrast, several studies have shown that other tailed phages have been unable to stimulate antibody production [20,51,52] or T-cell cytokine responses [53].…”