Sugar chain-recognizing antibodies and remedies for HIV infectious diseases

The present invention is directed to a sugar-chain-recognizing antibody which belongs to the IgM isotype and which recognizes Gg4Cer(Gal.beta.1-3GalNAc.beta.1-4Gal.beta.1-4Glc.beta.Cer) or GM2 which appears on HIV infected cells, as well as to a therapeutics for HIV diseases containing those IgMs.

TECHNICAL FIELD
 The present invention relates to novel sugar-chain-recognizing antibodies,
 and more particularly to antibodies which belong to the class IgM and
 which recognize sugar chains expressed in HIV-infected cells, as well as
 to remedies for treating HIV-patients containing the antibodies as
 effective ingredients.
 BACKGROUND ART
 AIDS (acquired immunodeficiency syndrome) was first discovered in San
 Francisco in 1981 as a fatal immunodeficiency disease of homosexual males
 (Gottlieb, M. S., Schroff, R., et al., N. Engl. J. Med., 305,
 1425-1430(1981)). Two years later, the Montanie group of the Pasteur
 Institute in France discovered the virus that causes AIDS (Barre-Sinoussi,
 F., Chermann, J. C., et al., Science, 220, 868-871(1983)). In 1985, this
 virus was univocally named HIV (human immunodeficiency virus) (Coffin, J.,
 Haase, A., et al., Science, 232, 697(1986)).
 AIDS is a disease having the following features and effects: When an
 individual is infected with HIV through sexual intercourse, blood
 transfusion, etc., the virus destroys the immunological functions of the
 infected individual, causing acquired immunodeficiency of the host, i.e.,
 the infected individual. Eventually, the host manifests a variety of
 symptoms such as diarrhea and pneumonia, resulting in a final outcome of
 death of the host.
 Presently, many researchers are attempting to develop remedies for AIDS.
 For example, since the discovery of azidothymidine (AZT) by Mitsuya et al.
 (Mitsuya, H., et al., Proc. Natl. Acad. Sci., USA., 82, 7096(1985)), ddI
 (2',3'dideoxyinosine), ddC (2',3'-dideoxycytidin), and other substances
 have been studied in clinical situations. However, pharmaceuticals
 providing satisfactory results have not yet been reached.
 Although the incubation period from infection with HIV to onset of disease
 greatly varies depending on the individual, about 50% of humans who are
 infested with HIV manifest the disease with certainty within 10 years
 after infection, and almost all the infected patients die within 1 to 3
 years after manifestation of the disease. Adults over 40 years of age and
 children rapidly develop the disease after they are infected with HIV.
 Reasons that explain the grace period between infection and development of
 AIDS-related complex (ARC) may include the patients' general health
 conditions, genetic predisposition, complications with other infection
 disease, and other host-dependent causes, as well as differences in the
 strain of infectious virus.
 In cases of infection due to transfusion of blood components, most
 HIV-infected individuals manifest AIDS and die. However, some infected
 individuals do not manifest AIDS even after 10 years have passed after
 infection, and some other infected individuals take an even longer time
 before manifestation of AIDS. Such cases are seen worldwide, and it has
 been reported that 5% of HIV-infected individuals survive for long
 periods. So-called long-time survivors among HIV-infected persons, who
 stay asymptomatic for long periods, have received much attention, because
 they are considered to offer a clue for elucidation of the mechanism of
 their resistance to HIV virus or preventing the manifestation of the
 pathological symptoms. Therefore, a variety of studies and research have
 been performed on such long-time survivors.
 However, the reason why longtime survivors do not manifest AIDS in spite of
 having been infected with HIV has not yet been clearly understood. Thus,
 it is desired to clarify the reason of HIV resistance, and to develop
 remedies for treating HIV diseases on the basis of the reason.
 DISCLOSURE OF THE INVENTION
 The present inventors studied the difference between the silent cases and
 active cases of virus replication among HIV-infected persons. During the
 studies, they found that specific IgMs found among natural antibodies for
 certain sugar chains carried by some infected patients might explain the
 delay of disease development. The sugar chains that serve as antigens are
 considered not to exist in the body under usual circumstances' or to exist
 in a limited amount. However, when cells are infected with HIV, the sugar
 chains appear on the surfaces of T cells or macrophages. (Generally
 speaking, it is well known that then cells becomes tumor or are infected
 with a virus, special sugar chains appear on the surfaces of the cells).
 If antibodies for such sugar chains belonging to the class IgM are present
 in serum as natural antibodies, the antibodies recognize HIV-infected
 cells and are bound to the infected alls. Complements cascade is activated
 at the local site, where IgM bound to the sugar antigen, and results in
 lysis of the HIV-infected cells. Thus, serum that contains the
 aforementioned natural IgM antibodies establishes a special environment in
 which HIV-infected cells do not easily proliferate. Also, the present
 inventors found that the HIV-infected cells have enhanced complement
 sensitivity. These facts have been confirmed not only in vitro but also in
 patients who had been infected with HIV whose manifestation of AIDS was
 delayed. Namely, it was actually confirmed that such long lived patients
 bare antibodies belonging to the class IgM that are reactive with
 HIV-infected cells.
 It was also found that cells that are usually resistant against complements
 are lysed by the complements after antibodies for gangliotetraose (Gg4)
 are bound to such cells. In addition, antibodies Belonging to the class
 IgM having binding capacity to the infected cells eliminate infected cells
 as a result of cytolysis mediated by complements activation and make a
 hole to the HIV infected cells. Accordingly, it has been learned that
 administration of antibodies belonging to the class IgM a nd having
 reactivity with HIV-infected cells is useful for the treatment of
 HIV-carriers.
 Accordingly, the present intention provides a sugar-chain-recognizing
 antibody which belongs to the class IgM and which recognizes
 Gg4Cer(Gal.beta.1-3GalNAc.beta.1-4Gal.beta.1-4GlcCer) or GM2.
 The present invention also provides a remedy for HIV diseases (AIDS)
 containing the sugar-chain-recognizing antibody as an effective substances
 The present invention also provides a composition for treating HIV diseases
 with the sugar-chain-recognizing antibody.
 The present invention also provides the use of the sugar-chain-recognizing
 antibody and the manufacturing method for a thrapeutics for HIV diseases.
 The present invention also provides a method for treating HIV-infected
 patients, which is characterized by the administration of an effective
 amount of the sugar-chain-recognizing antibody to HIV patients.

BEST MODE FOR CARRYING OUT THE INVENTION
 As used herein, sugar chains are represented by customary abbreviations in
 the art; Gg stands for ganglio, Cer for ceramid, Gal for galactose, GalNAc
 for N-acetylgalactose, and Glc for glucose. The antibodies of the present
 invention may be separated from human serum, or they may be prepared
 through a conventional method for raising antibodies using Gg4Cer or GM2
 as the antigen, so long as the antibodies recognize Gg4Cer or GM2
 (ganglioside GM2: II.sup.3.alpha.NeuAc-GgOse.sub.3 Cer) and belong to the
 immunoglobulin class as IgM.
 In order to separate the antibodies of the present invention from human
 serum, these may be used ordinary methods for screening the presence of
 antibodies employing Gg4Cer or GM2 as an antigen. The serum may be one
 collected from sero negative HIV-infected patient or others derive from
 healthy individual. The antibody against Gg4Cer or GM2 may be obtained
 through a conventional method such as a hybridoma method or a method using
 EB virus immortalization.
 Techniques that may be use(for the screening include conventional ELISA,
 RIA, fluorescent antibody technique, dot-immunobinding assay, the Western
 blotting method, and the .sup.51 Cr-release method.
 After being separated from the aforementioned sera, the antibodies of the
 present invention may be purified easily using well-known immunoglobulin
 purifying methods. Examples of such means include salt precipitation, gel
 filtration, and affinity chromatography (using i mannan column with which
 a mannose polymer is coupled for removing mannose binding protein (MBP).
 The antibodies of the present invention may also be prepared through a
 conventional hybridoma method using Gg4Cer or GM2 as the antigen. The
 antibodies of the invention may be monoclonal or polyclonal, so long as
 they recognize Gg4Cer and/or GM2 and belong to IgM class.
 The antibodies of the present invention are useful for the treatment of HIV
 diseases, as can be confirmed from the following.
 The present inventors obtained a human serum sample that had a capacity of
 causing cytolysis of HIV-1 infected T cell lines. A human T cell line
 (MOLT4) infected with the HTLV-IIIB strain of HIV-1 was found to be lysed
 by fresh normal human serum (NHS) from a healthy individual who was
 HIV-seronegative, although most of serum examined, including HIV-infected
 carriers' sera, were not active to lysis the HIV infected Molt 4. When a
 fresh sample was again taken one year after the initial sample was
 obtained, the serum with ability to lyse HIV-infected ce ls was still
 potent to the same extent. The cytotoxic capacity of NHS-1 was abolished
 by heating the serum at 56.degree. C. for 30 minutes, and was restored by
 the addition of a non-lytic fresh serum (NHS-5), indicating that the
 cytolysis had been mediated by complements activation, because heat
 treatment is known to inactivate complements.
 Mannose-binding protein (MIP) in serum has been reported to react with gp41
 (C. F. Ebenbichler et al., J. Exp. Med., 174, 1417 (1991)) and gp120 (C.
 Sual et al., J. Immunol. Med., 152, 6028 (1994)) of HIV, to thereby
 exhibit complement activities. However, when MBP was removed from NHS-1
 using a mannan column, cytolytic capacity was not reduced.
 After fractionation of NHS-1 by gel filtration on a TSK gel G3000 SW
 column, the IgM fraction was found to have the capacity to sensitize
 HIV-infected MOLT4 cells (HIV-MOLT4) for cytolysis by non-lytic human
 serum such as NHS-5. The fraction completely lost its sensitizing capacity
 abolished by being passed through an affinity column coupled with a mouse
 anti-human IgM monoclonal antibody. This explains that IgM is responsible
 for the sensitization of HIV-MOLT4 to cytolysis by serum complements.
 However, this IgM did not react with HIV antigens in Western blot
 analysis. Therefore, the present inventors speculated that the antigenic
 epitope(s) recognized by this antibody might be altered sugar moieties
 produced due to HIV-infection. The inventors then attempted to treat
 uninfected MOLT4 cells with neuraminidase, and found that the treated
 cells were reactive with the IgM, which recognize a sialoglyco conjugate.
 Furthermore, absorption of the IgM fraction with these
 neuraminidase-treated MOLT4 cells significantly reduced sensitization to
 cytolysis by normal human serum.
 The IgM fraction showed reactivity with certain glycosides, such as
 Gg4Cer(Gal.beta.1-3GalNAc.beta.1-4Gal.beta.1-4Glc.beta.Cer), which can be
 generated by removed of sialic acid from GM1. Furthermore, liposomes
 bearing Cg4 absorbed the sensitization capacity of the IcM for cytolysis.
 The presence of Gg4 antigen-recognition sites on HIV-MOLT4 cells and on
 neuraminidase-treated MOLT4 cells was confirmed by immunostaining with
 mouse anti-Cg4 monoclonal antibody. These actions were also confirmed with
 IgM that recognized GM2 antigen or HIV-infected V-937 cells.
 On the other hand, complement activities are known to be suppressed by
 specific membrane inhibitors such as (1) a decay accelerating factor which
 is a inhibitor for membrane complements (DAF; A. Nicholson-Weller, J.
 Burge, D. T. Fearon, P. F. Weller, K. F. Austen, J. Immunol., 129, 184
 (1982)), (2) membrane cofactor proteins (MCP; T. Seya, J. R. Tumer, J. P.
 Atkinson, J. Exp. Mel., 163, 837 (1986)), and (3) CD59 (HRF20; 20 kDa
 homologous restriction factor, N. Okada, R. Harada, T. Fujita, H. Okada,
 Int. Immunol., 1, 205 (1989); A. Davis et al., J. Exp. Med., 170, 637
 (1989)).
 Under conditions in which Fas antigen was expressed, expressions of DAF,
 MCP, and CD59 were down-regulated, whereas expression of HLA-DR retained
 unchanged. In particular, expression of CD59 on HIV-infected cells was not
 greater than 50% that of uninfected MOLT4 cells. Down regulation of CD59
 expression was also evident from the level of mRNA as determined by
 Northern blot analysis.
 Moreover, HIV-infected-MOLT4, whose resistivity against complement reaction
 is weakened due to reduced expression of CD59, is subject to selective
 cytolysis by IgM and normal human serum complements. There was no
 difference in the extent of gp120 expression between lysed and unlysed
 cells. The down regulation of DAF, MCP and particularly of CD59, might
 contribute to cytolysis of the HIV-infected cells by human complements
 activated by antigen-IgM complex. Furthermore, a reduction in the amounts
 of terminal sialic acid on the membranes of HIV-infected cells might
 facilitate the activation of complements. However, HIV-infected cells are
 not lysed by HIV-seronegative serum complements even though the cells
 bound IgG that can be detected by fluorescein-labeled anti-human IgG
 antibodies.
 For complement activation by IgG via the classical pathway, two IgG
 molecules reacting in close proximity to each other, are required. On the
 other hand, only one molecule of IgM is sufficient for complement
 activation. Therefore, complement activation can be triggered much more
 efficiently by IgM than by IgG.
 Furthermore, it is possible that complement activation initiated by IgM may
 escape from restriction by complement-inhibiting molecules on the target
 cell membranes, since IgM is a large molecule having a molecular size of
 900 kDa and complement components bound to the molecule might not be
 accessible to DAF, MCP, or other complement-inhibiting molecules on the
 membranes. On the other hand, membrane attack complexes generated by the
 activation of complements bind to the lipid bilayer of cell membranes.
 CD59 restricts the formation of these antigen-2gM complexes that are bound
 to the membranes, and thereby prevent cell damage. Reduced expression of
 CD59 on HIV-infected cells revert the resistance of cells against membrane
 attack complexes and accelerates cytolysis.
 The same results as with MOLT4 cells were obtained with other T cell lines
 such as CEM and MT4 cells. HIV-infected CEM cells showed reduced CD59
 expression and were sensitive to cytolysis by the IgM and complements.
 However, no reduction in CD59 expression was observed in macrophage cell
 lines such as HIV-infected U937 cells, and these cell lines were resistant
 to cytolysis mediated by the IgM and complements.
 Cytolytic reactions mediated by IgM and complements may play a role in vivo
 in the elimination of HIV-infected T cells. If an individual has natural
 IgM antibodies reactive with sugar antigens, such as Gg4 and GM2, that
 appear on HIV-infected T cells, it is considered that expansion of HIV
 infection may be suppressed upon HIV infection. Although HIV--infected
 macrophages may survive the attacking reaction involving IgM and
 complements and may remain as a reservoir of HIV, infected T lymphocytes
 will be removed. Thus, serum of IgM would be a key factor in a mechanism
 responsible for the long-term survival of some HIV-carriers. In fact, when
 twenty long-term survivors who lad survived 12 years or more after
 infection with HIV were studied, all of them were found to possess IgM,
 whereas five individuals who manifested symptoms within short periods
 possessed only IgG and did not possess IgM.
 A similar protective mechanism of IgM has also been found with melanoma
 patients (Ores, P. C., Sze, L. L., Morton, D. L. and Irie, R. F., J. Natl.
 Cancer Inst., 66, 249, 1980).
 As described above, administration of the sugar-chain IgM of the present
 invention to HIV-infected patients would be effective in retaining natural
 antibodies in the body, and thus would be effective in the treatment and
 prevention of AIDS.
 The IgM of the present invention is generally incorporated into suitable
 drug preparations typified by parenteral preparations such as injections,
 and is administered to patients in need of treatment. Such preparations
 may be obtained through customary methods, and vehicles for the
 preparations may be conventional and general ones such as sugar, amino
 acids, and proteins. The preparations contain--in addition to the IgM of
 the present invention--suitable additives such as a variety of inorganic
 salts in suitable amounts. The dose of the preparations of the present
 invention in various forms is not particularly limited. It is generally
 preferred that the dose be determined to exhibit activity such that the
 IgM is present in an amount ranging from 10 .mu.g/ml to 50 .mu.g/ml in
 vitro with respect to the effective ingredient sugar chains (IgM potency)
 and kills HIV-infected cells.
 Thus, the antibodies of the present invention are useful for the prevention
 and treatment of HIV-infected patients. That is, when the sugar-chain
 specific antibodies of the present invention are administered to an
 individual, natural antibodies titer are raised in vivo, to thereby
 provide therapeutic and preventive effects against AIDS.
 EXAMPLES
 The present invention will next be described in more detail by examples.
 Example 1
 Culturing of Cells
 MOLT4 cells, a human T cell line, were grown in RPMI 1640 medium
 supplemented with 10% fetal calf serum (FCS), 2 mM glutamine, 100 IU/ml
 penicillin and 100 mg/ml streptomycin, and were kept free from mycoplasma.
 The cells were infected with HLTV-IIIB (HIV-1) and cultured for 4 weeks or
 more before being used as a source of HIV-infected terget cells. More than
 95% of the cells were HIV-env antigen (gp120) positive as detected by flow
 cytometry using a monoclonal antibody 0.5.beta. (i.e., an antibody for
 gp120 of HTLV-IIIB), thereby confirming that infection with HIV-l
 prevailed among most of the cells.
 5.times.10.sup.6 HIV-infected MOLT4 cells and uninfected control MOLT4
 cells (normal MOLT4) were separately labeled with .sup.51 Cr. After
 labeling, cells were both washed and resuspended in serum free RPMI 1640
 medium at a concentration of 2.times.10.sup.5 /ml.
 A 100 .mu.l aliquot of the cell suspension and 100 .mu.l of each of fresh
 or heat-inactivated sera were placed in each well of U-bottom microplates.
 The sera were obtained from four HIV-seropositive patients and thirteen
 healthy HIV-seronegative donors.
 The plates were incubated at 37.degree. C. for 1.5 hours and centrifuged.
 The percentage of .sup.51 Cr release into the cell-free supernatant was
 computed by the following equation:
 ##EQU1##
 Example 2
 Treatment with Neuraminidase
 One hundred (100) .mu.l of neuraminidase were added to 100 .mu.l of cell
 suspension (2.times.10.sup.6) and incubated at 37.degree. C. for 45
 minutes. To cell pellets of 2.times.10.sup.6 MOLT4, Neu-MOLT4, or
 HIV-MOLT4, 250 .mu.l of an IgM fraction (250 .mu.g/ml) from NHS1--the
 serum that exhibited strong cytolysis activity were added and incubated at
 4.degree. C. for 30 minutes. After centrifugation, the supernatants were
 transferred to other tubes for determination of their sensitizing
 capacity. The cells were washed and stained with FITC-conjugated mouse
 anti-human IgM and analyzed on a FACScan.
 The supernatants obtained after incubation with MOLT4, Neu-MOLT4, or
 HIV-MOLT4 were incubated with HIV-MOLT4 in the presence of non-lytic human
 serum (NHS-5) to determine the cytolysis activity.
 Example 3
 Ninety-five serum samples from healthy individuals were subjected for
 screening as described in Example 1 in which infected MOLT4 cells labeled
 with .sup.51 Cr were used as target. As a result, 16 individuals were
 found to exhibit 15% or higher cytolysis activity for infected cells.
 Subsequently, through use of infected U937 and MOLT4 cells, selection was
 made to two serum samples that Exhibited cytolysis activity to these two
 infected cell lines. The IgM fractions of the sera were collected and used
 in the following experiment.
 Liposomes were prepared in accordance with the method described in
 Immunology, 48: 129-140 (1983). Briefly, cholesterol,
 dimyristoyl-phosphatidylcholine, and one of a variety of lipids to be
 inserter were mixed at 1:1:0.1, and the solvent chloroform was evaporated
 with a rotary evaporator, to thereby create a lipid film on the interior
 surface of the flask. Control liposomes were prepared from cholesterol and
 dimyristoyl phosphatidylcholine (1:1) PBS was added to the lipid film, and
 the film was vigorously vibrated in a vortex mixer so as to form liposomes
 (multi-layered). PBS was added to the multi-layered liposomes for
 centrifugal washing, to thereby form a liposome suspension.
 From the resultant liposome suspension, an aliquot containing 10 nmol
 glycolipids taken and subjected to centrifugation to thereby obtain a
 liposome pellet. The supernatant was discarded. To the pellet was added
 the IgM fraction (200 .mu.g/200 .mu.l) (after fractionation of
 seropositive serum through gel Filtration using TSK-3000). The mixture was
 stirred and allowed to stand at room temperature for 60 minutes so as to
 absorb antibodies for glycolipids present on the liposome membranes. After
 reaction, the mixture was centrifugated to precipitate the liposomes, and
 the supernatant was recovered.
 The IgM fraction after the above absorption procedure was examined for the
 cell damaging activity to HIV-infected MOLT4 cells (HIV-MOLT4). Briefly,
 to 100 .mu.l of .sup.51 Cr-labeled HIV-MOLT4 (i.e., .sup.51 -HIV-MOLT4,
 2.times.10.sup.5 /ml), or in the case of control, to the same amounts of
 uninfected .sup.51 -MOLT4 , were added 50 .mu.l of ar IgM fraction which
 had or had not undergone the absorption procedure and 50 .mu.l of
 seronegative normal human serum (as a source of complements). The mixture
 was allowed to react at 37.degree. C. for 90 minutes, and then the plates
 were centrifugated. The amount of .sup.51 Cr released into the supernatant
 was measured to obtain the level of damage to the cells.
 That is, the control liposomes, Gg4 liposomes, and GM2 liposomes, which
 were liposomes only, liposomes plus Gg2, and liposomes plus GM2,
 respectively, were used in the test. An antigen-antibody reaction was
 caused through use of one type of the liposomes, fresh serum, and a 25%
 IgM fraction. The cell lysing activity (% cytolysis) was determined in the
 supernatant. The results are shown in FIGS. 1 and 2. In both cases of
 sample No. 1 and No. 2, the lysing activity remained in "control" and "Gg4
 iposomes," and this activity was completely eliminated upon contact with
 GM2 liposomes. From these results, it was confirmed that, in sera from
 healthy individuals, GM2 was the antigen epitope for IgM natural
 antibodies produced against HIV-infected cells.
 Experiment Example 1
 Cytolysis of HIV-MOLT4 Cells by Human Serum (containing IgM) from an
 Individual Who is a Healthy Seronegative Donor
 The results are shown in FIG. 3. The x-axis represents % cytolysis, and the
 y-axis represents sera from donors (NHS-1 through NHS-13 and PS-1 through
 PS-4). FIG. 3 is accompanied by charts (a) and (b) which show the results
 of immunostaining performed after reaction of a serum sample (NHS-1,
 NHS-5, or PS-1) with HIV-MOLT4 cells (x-axis: fluorescence intensity;
 y-axis: cell number), wherein chart (a) is drawn to the case in which IgM
 was used, and chart (b) is drawn to the case in which IgG was used. From
 these charts, the following observation become evident.
 (A) Of the thirteen (13) sera from healthy HIV-seronegative donors, only
 one (NHS-1) caused cytolysis of .sup.51 Cr-labeled HIV-MOLT4 cells
 attributed to the human serum.
 NHS-1 showed as high as 43% cytolysis, whereas no other serum from healthy
 individuals (twelve individuals from NHS-2 to NHS-13) showed any
 noticeable cytolysis. The sera from HIV-seropositive patients (PS-1 to
 PS-4) showed almost no cytolysis.
 (B) HIV-MOLT4 cells were incubated with an equal volume of a serum sample,
 NHS-1 NHS-5, or PS-1, at room temperature for 30 minutes. The cells were
 then washed and immunostained by the use of FITC-labeled anti-human IgM
 antibody or FITC-labeled anti-human IgG antibody.
 The results are shown in carts (a) and (b) of FIG. 3. The HIV-MOLT4 cells
 treated with NHS-1 was bound to the anti-IgM antibody, whereas PS-1 which
 was bound to the anti-IgG antibody, did not react with the anti-IgM
 antibody.
 Experiment Example 2
 Neuraminidase-treated MOLT4 cells, untreated MOLT4 cells, or HIV-MOLT4
 cells were treated with an IgM antibody fraction from NHS-1, and then
 immunostained with fluorescein-labeled anti-human IgM antibody. The
 results are shown in FIG. 4 similar to chart (a) of FIG. 3. The IgM
 antibody that reacted with HIV-MOLT4 cells also reacted with
 neuraminidase-treated HIV-MOLT4 cells.
 As a result, as shown in chart (a) of FIG. 4, the IgM fraction from NHS-1
 reacted with Neu-MOLT4 cells as strong as its reaction to HIV-MOLT4 cells.
 The anti-gp120 monoclonal antibody (anti-gp120, 0.5.beta.) stained only
 HIV-MOLT4 cells as shown in chart (b) of FIG. 4.
 The sensitizing capacity of the IgM fraction for cytolysis by human serum
 was absorbed by treatment with Neu-MOLT4 cells as was absorbed by
 treatment with HIV-MOLT4 cells. In other words, the IgM fractions treated
 with these cells for absorbing their cytolysis capacity lost the potency
 for imparting the healthy human serum (NHS-5) with cytolysing power.
 Experiment Example 3
 IgM that is reactive to HIV-MOLT4 reacts with Gg4Cer.
 (A) Seven different types of glycolipids described below were
 chromatographed on a plastic TLC plate, to thereby detect spots through
 immunostaining by the use of orcinol-H.sub.2 SO.sub.4 reagent and the IgM
 fraction obtained from NHS-1 (a), and also through TLC immunostaining by
 the use of the IgM fraction obtained from NHS-1.
 1. LacCer, 2. Gg3Cer, 3. nLc4Cer, 4. Lc4Cer, 5. Gb4Cer, 6. Gg4Cer, 7.
 IV.sup.3 Gal.alpha.-nLc4Cer.
 Gg4Cer was significantly stained. LacCer, Gg3Cer, and LcCer were slightly
 stained. However, the IgM fraction barely reacted with nLc4Cer, Gb4Cer,
 IV.sup.3 Gal.alpha.-nLc4Cer, sialylated glycolipids such as GM3, GM2, GM1,
 GD1a, GT1b, GQ1b, IV.sup.3 NeuAc.alpha.-nLc4Cer, sialyl Le.sup.a and
 sialyl Le.sup.x.
 Levels of staining relative to Gg4Cer, level of which was taken as 100,
 were 25.8, 31.3, 0, 29.3, 0, and 24.6 for LacCer, Gg3Cer, nLcCer, Lc4Cer,
 Gb4Cer, and IV.sup.3 Gal.alpha.-nLc4Cer, respectively.
 Liposomes were prepared as described by Okada and others (Okada, N.,
 Yoshida, T., and Okada, H., Nature, 299, 261 (1982)). An IgM fraction (50
 .mu.g/200 .mu.l) was mixed with 5 nmol of each liposome preparation. After
 centrifugation, the cytolysis activity of supernatants was determined in
 accordance with the method described in Example 2.
 The capacity of the IgM fraction for cytolysis of HIV-MOLT4 cells by
 non-lytic human serum (NHS-5) was absorbed by treatment with Gg4-liposomes
 to a level lower than half (FIG. 5, A).
 Although mouse monoclonal antibody against Gg4 did not react with normal
 MOLT4 cells, Lt reacted more with HIV-MOLT4 and Neu-MOLT4 cells as
 determined by flow cytometry analysis (FIG. 5, B).
 Experiment Example 4
 Significant Decrease in CD59 on HIV-MOLT4 Cells
 (A) Through flow cytometry analysis, expression of complement regulatory
 membrane actors (DAF, MCP, and CD59) on HIV-infected cells was found to be
 reduced. Expressions of Fas antigen and HLA-DR remailed unchanged after
 HIV-infection (FIG. 6).
 (B) For Northern blot analysis of complement regulatory membrane factors, 5
 .mu.g of total RNA from uninfected (N) and HIV-infected (H) MOLT4 cells
 were extracted and denatured with glyoxal and DMSO as described in Thomas,
 P. S., Method Enzymol., 100, 255-2 (1983). cDNA fragments of CD59, DAF,
 MCP, and GAPDH (glyceraldehyde-3-phosphate-dehydrogenase) were used as
 probes. Reduction of CD59 mRNA was clearly observed.
 After 1.times.10.sup.6 cells were incubated with NHS-1 for 30 minutes at
 37.degree. C., two color analysis was performed on HIV-MOLT4 . Dead cells
 were detected by staining with propiodium iodide (PI). This allows
 discrimination of dead cells which are stained with PI and living cells
 which are not stained with PI. C5b-9 (MAC), CD59, and gp120 were stained
 with FITC-labeled monoclonal antibodies to these antigens. The results are
 summarized as follows.
 (a) PI-stained cells (dead cells) after incubation with NHS-1 were stained
 a little more strongly than PI-staining negative cells, the latter cells
 indicating that these cells treated with larger amounts of C5b-9 and were
 not killed.
 (b) NHS-1 does not induce PI positive dead cell in the presence of 10 mM
 EDTA.
 (c) Cells expressing lower amounts of CD59 were stained with PI after the
 treatment with NHS-1, indicating that cells expressing lower level of CD59
 were preferentially killed.
 (d) Expression of gp120 was essentially the same between PI-stained cells
 (dead cells) and unstained cells (living cells), indicating that the
 amount of anti-gp120 antiboday and cell-killing capacity of NHS-1 are not
 directly related.
 INDUSTRIAL UTILITY
 Since administration of the sugar-chain-recognizing antibody to
 HIV-infected indivisuals cause cytolysis of HIV-infected cells through
 mediation of activation of complement, the sugar-chain-recognizing
 antibody of the present invention is useful in the treatment and
 prevention of AIDS.