Oka Vaccine Virus Research Articles

A Varicella Outbreak in Diffuse Large B-Cell Lymphoma Patients Receiving Rituximab-Containing Chemotherapy

Background: Varicella, characterized by a vesicular rash, occurs primarily in young children. Although older individuals can also be affected or vaccinated, outbreaks among adults are rare. We experienced sequential four cases of varicella after an index herpes zoster case in hematological wards.Methods: All varicella cases were confirmed varicella zoster virus (VZV) infection by PCR. We analyzed presence of anti-VZV IgG and IgM antibodies at the first hospital admission (cryopreserved serum) and the onset of VZV infection by enzyme immunoassay. To identify VZV-positive specimens and to differentiate these strains from the Oka vaccine virus, PCR designed to target the initial part of VZV open reading frame (ORF) 62 was performed on PBMCs or vesicular swabs. Furthermore, we investigated the incidence of localized zoster and generalized zoster/ varicella in rituximab administered patients. Between January 2010 and December 2013 (48 months), we collected data including the number ofrituximab administered patients, rituximab administration, localized zoster patients, and generalized zoster/varicella patients.Findings: All varicella cases occured in diffuse large B-cell lymphoma patients receiving rituximab-containing chemotherapy (Table 1). On the other hand, only three of the 18 non-varicella patients in the same room were receiving rituximab-containing chemotherapy (P= 0.005, Table 2). Furthermore, all varicella patients had anti-VZV IgG antibody at the first hospital admission (Table 1). Sequencing the first part of ORF 62 in these cases showed the identical sequences and could be distinguished from the Oka vaccine virus, Oka parental virus and Dumas strain. During the 48 months, there were 340 patients who received rituximab. The total number of rituximab administrations was 2086. There were 29 patients with localized zoster (8.5%), and 5 patients with generalized zoster/varicella (1.4%). Four of these patients constituted the cluster reported here. The incidence of generalized zoster/ varicella for 2 months in this case was significantly higher than another 46 months (p<0.001).Conclusions: Even in the presence of neutralizing antibodies to the virus, lymphoma patients treated with rituximab-containing chemotherapy can possibly become re-infected with varicella. These findings suggest that zoster patients should be strictly isolated in hematology and oncology ward, and prophylactic acyclovir should be considered for such patients when exposed to zoster/varicella.Abstract 5439. Table 1Patient characteristicsCaseAgeWardTreatment and onsetDisease typeOnset WBC (x109/L)Onset Lymphocyte (x109/L )Onset serum VZV copy (Copies/mL)preserved IgG (EIA)Onset IgM (EIA)Onset IgG (EIA)Duration of ACV (Days)Complication175A2ndrelapse #1 R-EPOCH Day30Zoster3.60.65NDNDNDND8None250APrimary #8 R-CyclOBEAP Day1varicella1.70.021.0×1067.5<0.80512None381Bprimary #3 R-CHOP Day14varicella5.00.031.7 × 1075.8<0.80<2.044* Hepatitis DIC463Aprimary #3 R-CyclOBEAP Day8varicella11.80.352.7 × 10417.8<0.8013.55None568B2ndrelapse After #4 R-DeVIC +Rx24Gyvaricella2.20.292.6 × 1032.8<0.802.47NoneR-EPOCH (rituximab, etoposide, prednisolone, vincristine cyclophosphamide and doxorubicin); R-CyclOBEAP (rituximab, cyclophosphamide, vincristine, etoposide, bleomycin, doxorubicin and prednisolone); R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone); R-DeVIC (dexamethasone, etoposide, ifosfamide and carboplatin); Rx, radiotherapy: ND, not done: ACV, acyclovir: DIC, disseminated intravenous coagulation; * treatment dose.Table 2Patients and control cohort characteristics.Varicella (N = 4)Without varicella (N = 18)PAge(median/range)66/50–6868/37–820.966Male gender418-History of chemotherapy (%)4 (100)8 (44)0.096Rituximab administered (%)4 (100)3 (17)0.005WBCx109/L (median)3.63.30.898Lymphocytex109/L (median/)0.160.950.068Albuming/dL (median)3.63.90.392Creatininemg/dL (median)0.710.720.831ASTIU/L (median)18220.670These data were at onset or exposure. WBC: white blood cell, AST: aspartate aminotransferase, T-Bil: total bilirubin. DisclosuresNo relevant conflicts of interest to declare.

Molecular Analysis of the Oka Vaccine Strain of Varicella‐Zoster Virus

Live attenuated Oka vaccine was subjected to molecular analysis, with the long-term goal of identifying genes in the vaccine strain responsible for its attenuation. Complete genomic sequences for both the Oka parent virus and the Oka vaccine virus were determined and compared. There were differences in only 42 bases between the 2 viruses. More than one-third (15/42) of the nucleotide substitutions in V-Oka were found in open reading frame (ORF) 62. These differences were also observed when sequences of Japanese low-passage clinical isolates of varicella-zoster virus (VZV) were compared with the Oka vaccine strain. The ORF62 gene encodes an immediate early (IE) protein, IE62, that is the major transactivator of VZV and, as such, is critical to initiating the VZV gene expression cascade. Several insertions and deletions were also observed in comparing the 2 sequences, largely in the internal tandem repeat units. Functional differences between the 2 types of Oka virus were also examined. Oka vaccine was found to consist of a mixture of different subpopulations, and the parental Oka virus replicates more efficiently than does the vaccine strain. Development of a bacterial artificial chromosome for VZV expression should lead to the discovery of additional differences in wild and vaccine types and, thus, enhance our understanding of the genetic basis for attenuation of the Oka vaccine strain.

Long-term persistence of cellular immunity to Oka vaccine virus induced by pernasal co-administration with Escherichia coli enterotoxin in mice

A mutant of Escherichia coli enterotoxin induced cellular immunity to a live varicella vaccine (the Oka strain) as a mucosal adjuvant in mice. The persistence of this cellular immunity was investigated. A commercially available live Oka vaccine virus and toxin were administered once simultaneously via the nasal route, in mice. Ten or 12 months later, a delayed-type hypersensitivity to the vaccine virus was detected by footpad test, but an antibody neutralizing the varicella-zoster virus was not. When spleen cells from mice immunized with the vaccine and toxin were re-stimulated by live vaccine in vitro, their thymidine uptake and IL-2 production were higher than those from mice immunized with the vaccine alone, but lower than those of spleen cells prepared from mice 2 months after nasal administration. Production of IL-4 in these cells, however, was not induced by re-stimulation in vitro. These results suggest that although humoral immunity for Oka vaccine virus is only weakly induced by one co-administration of the vaccine and toxin, cellular immunity is induced and maintained over 1 year, though it declines with age. The nasal administration of the vaccine and toxin might be effective for maintaining cellular immunity to the varicella-zoster virus long term.

Adjuvant action of Escherichia coli enterotoxin for delayed-type hypersensitivity to Oka vaccine virus on pernasal co-administration in mice

The usefulness of a mutant of Escherichia coli enterotoxin for the induction of cellular immunity to varicella-zoster virus as a mucosal adjuvant is assessed in mice. When a commercially available live varicella vaccine (the Oka strain) and toxin were once administered simultaneously via the nasal route, delayed-type hypersensitivity to Oka vaccine virus was significantly induced and detected by footpad test in mice. Moreover, when spleen cells from mice immunized with the vaccine and toxin were re-stimulated with live vaccine in vitro, they showed more thymidine uptake and produced more IL-2 than those from mice immunized with the vaccine alone. These results suggest that mutant enterotoxin has adjuvant action to induce a specific delayed-type hypersensitivity to Oka vaccine virus on nasal co-administration with live vaccine virus.

Identification of the Oka strain of the live attenuated varicella vaccine from other clinical isolates by molecular epidemiologic analysis.

A method was developed to distinguish the Oka vaccine strain of varicella-zoster virus (VZV) from other clinical isolates. The molecular characteristics of 52 clinical isolates from varicella or zoster patients with no history of VZV vaccination and the Oka strain, including vaccine and parental viruses, were analyzed by PstI cleavage of the PstI site-less (PSL) region. This was followed by single-strand conformational polymorphism (SSCP) after polymerase chain reaction amplification of repeating region 2 (R2). Most of the clinical isolates tested, especially recent isolates, had a PstI site in the PSL region, but the Oka strain did not. The SSCP patterns of R2 in Oka strain virus differed from those of other viruses. These results suggest that analysis of the PstI site followed by SSCP of R2 will be useful for identifying the Oka vaccine virus in isolates.

A detailed analysis of transcripts mapping to varicella zoster virus gene 14 (glycoprotein V)

We have characterized in detail those transcripts mapping to the varicella zoster virus (VZV) glycoprotein V (gpV) open reading frame (ORF). The analyses revealed that a major 1.95-kb and a minor 2.5-kb transcript map to these sequences for VZV strain Scott, with 1.8- and 2.3-kb transcripts in a vaccine Oka strain, consistent with intragenic repeat (R2) copy number differences. The transcripts for each strain are 5′ coterminal, are polyadenylated, and do not seem to be spliced. Upstream of the cap site there are few obvious regulatory consensus sequences, but there is a potential CCAAT box at −59 by and an unusual sequence at −25 to −33, ATTTAAATT, which may serve as the TATA box for this gene. The 3′ termini map 10 to 20 bases downstream from potential polyadenylation signals: ATAAA for the 1.95-kb transcript and ACGTAAA for the 2.5-kb transcript. This transcript pattern is quite different from that observed for the gpV homologue in herpes simplex virus (HSV-1), glycoprotein C (gC). Strain Scott synthesizes about 20-told more gpV-specific transcripts than a strain of the Oka vaccine virus, reflecting the amounts of gpV polypeptide accumulating in both strains; this implies that the defect in Oka gpV polypeptide production is at the level of transcription.

Differentiation of Oka varicella vaccine strain from wild varicella‐zoster virus strains isolated from vaccinees and household contact

The Oka varicella vaccine strain can be differentiated from wild-type strains by its unique restriction endonuclease fingerprinting (REFP: HpaI-K and EcoRI-P) pattern of the gpV-coding region of the varicella-zoster virus (VZV) genome. VZV-DNAs from patients with complicated clinical courses related to vaccination were examined to determine whether they were vaccine-derived or wild-type. A virus was isolated from a one year-old boy with acute lymphocytic leukemia (ALL) who developed typical varicella 28 days after vaccination (case A). Another virus was isolated from a four-year-old boy without clinical symptoms following household contact with varicella patients at the age of two months, and he developed zoster 14 months after vaccination (case B). Also, two strains (OK1 and OK2) were isolated from household contacts (mother and sister) with a vaccine with ALL in Oklahoma who developed varicella 18 days after vaccination (case C). In case C, BgII-REFP did not determine conclusively whether the two strains (OK1 and OK2) were vaccine-derived or wild-type because the patterns obtained were different from both the Oka varicella vaccine strain and American wild-type strains [Gelb et al., Journal of Infectious Diseases, 155:633-640, 1987]. All VZV strains examined in the present study were identified as wild-type by our method using HpaI-K and EcoRI-P fragments as marker fragments. Thus it is becoming evident that REFP using HpaI and EcoRI endonucleases is a convenient and reliable means of distinguishing between the Oka vaccine virus strain and wild-type viruses isolated from individuals developing vesicular rashes shortly and long after varicella vaccination.

Analysis of Varicella-Zoster Virus DNAs of Clinical Isolates by Endonuclease HpaI

The DNAs of 20 strains of varicella-zoster virus (VZV) isolated from epidemiologically unrelated individuals, and of 15 strains isolated from vesicles of vaccinees with varicella or zoster after vaccination, were compared by restriction enzyme cleavage using HpaI. Differences were found in the sizes of the HpaI-F, -G and -K fragments of the wild strains. The gel migration patterns of the HpaI-F and -G fragments, but not of the HpaI-K fragment, were polymorphic in the different strains isolated from the vaccinees. The effects of serial passages in vitro and in humans on the genome stability of VZV were investigated by HpaI analysis. The DNA profiles of the HpaI-K fragments from six isolates recovered from room-mates infected in a single outbreak were identical, but the mobilities of their HpaI-F and -G fragments varied. The DNA profiles of the Oka vaccine virus after 10 and 85 passages in human embryo cells differed only in the HpaI-F fragment. The profiles of these fragments in DNA derived from two isolates obtained at different times from a vaccinee with varicella followed by zoster were compared with those of the Oka (parental) and Oka (vaccine) strains, and identical results were obtained for the two viruses. In addition, the same DNA profiles of HpaI fragments were obtained from three sequential isolates from one person and also from two isolates from another with varicella and zoster. Thus, it was concluded that: three variable fragments (HpaI-K, -F and -G) were not changed in the DNAs of isolates derived from the same patient; HpaI-K was stable both on passage in vitro and after human transmission in the case of the same outbreak, but was different among all wild-type strains isolated in epidemiologically unrelated outbreaks; HpaI-F was very unstable both on passage in vitro and in human infections by either vaccine or wild-type strains; HpaI-G was not influenced by passage in vitro but varied among wild-type strains. Using physical maps of VZV DNA established by others, three variable regions on the viral genome were identified. One was located near the 0.16 coordinate, which is covered by HpaI-K (variable region I, VRI). Another was represented by HpaI-F (VRII), the most unstable fragment, and mapped at about the 0.35 coordinate. The third was VRIII near the right terminus, covered by HpaI-G.